YOKOGAWA ManualInstruction - HelpJuice · 2016-09-30 · im 12d7c2-01e-h f ail hold measure cal...

IM 12D7C2-01E-H4th Edition

InstructionManual

Model SC400Conductivity converter

YOKOGAWA

IM 12D7C2-01E-H

FAILHOLD

MEASURECALDISPLAYHOLD

YES NO

ENT

SETPOINTSRANGESET HOLDTEMP.SERVICE

*NO MODEYES

> ENT>

CONTACTS

MODE

m S / c mµ S / c m

S1

S2

S3

FAIL

k Ω / c m

M Ω / c m

ADJUSTMENT KEYSCHOOSE DIGITFOR ADJUSTMENTADJUST DIGIT (TO DECRE-ASE PASS THROUGHZERO)

ENT: ENTER NEW VALUE

MEASUREDVALUEDISPLAY

MESSAGEDISPLAY

KEY PROMPTFLAGS

SELECTION KEYSYES: ACCEPT

SETTINGNO: CHANGE TO

NEW SETTING

L

L

SELECT MODEMEASURE/MAINTE-NANCE

CAN BE USED TOESCAPE PROGRAMAT ANY TIME

CONTACT OUTPUTS

LEDS SIGNAL THE STATUS OFTHE CONTACTS

SELECT MODEMEASURE/COM-MISSIONING

OUTPUTHOLDFLAG

FAIL FLAGMENU POINTERFLAGS

MENU FORMAINTENANCEFUNCTIONS SEECHAPTER 5

MENU FORCOMMISSIONINGFUNCTIONSSEE CHAPTER 6

NOTE: First digit changes from 1, -1, - to blank.

IM 12D7C2-01D-H

CONTENTS

1. INTRODUCTION ..................................................................11-1. Application......................................................................11-2. Required component for conductivity measurement .......1

2. TECHNICAL SPECIFICATIONS ..........................................22-1. General technical specifications ......................................22-2. Functional specifications .................................................32-3. Environmental conditions ................................................42-4. Model specifications .......................................................42-5. Functional description.....................................................5

3. INSTALLATION AND WIRING .............................................73-1. Installation and dimensions .............................................73-2. System configuration ......................................................93-3. Wiring ........................................................................10

3-3-1. Preparation ........................................................103-3-2. Wiring of power supply.......................................133-3-3. Switching on the instrument ...............................133-3-4. Wiring the contact signals ..................................133-3-5. Wiring the analogue output signals.....................143-3-6. Wiring of the sensors..........................................15

4. START-UP ........................................................................164-1. General ........................................................................164-2. The DISPLAY functions.................................................16

4-2-1. The primary display ..........................................164-2-2. The secondary display .....................................164-2-3. Annunciators....................................................16

4-3. The output functions.....................................................164-4. The contact output functions ........................................174-5. The temperature compensation functions .....................174-6. The sensor characteristics ............................................174-7. Calibration ....................................................................174-8. Operations overview .....................................................18

5. MAINTENANCE..................................................................195-1. Calibrationg........................................CAL ...................205-2. Selecting a value to display ................DISPLAY............225-3. HOLD ouput function .........................HOLD.................24

6. COMMISSIONING..............................................................266-1. Adjusting the setpoints.......................SETPOINTS .......266-2. Range adjustment ..............................RANGE ..............286-3. Set-up the HOLD function..................SET HOLD .........306-4. Temperature compensation ...............TEMP.................32

7. TROUBLE SHOOTING ......................................................347-1. Introduction ..................................................................347-2. Sensor selection ...........................................................347-3. Diagnostics...................................................................357-4. Check during operation ................................................357-5. Error messages and explanation...................................36

8. SERVICE MODE.................................................................378-0. Access to service settings.............................................398-1. Temperature sensor and unit ........................................408-2. Cell constant.................................................................408-3. Measuring principle.......................................................418-4. Analogue current output signal .....................................418-5. Linear/non-linear output selection .................................428-6. Table for a non-linear output range ...............................428-7. Temperature output signal ............................................448-8. Functioning of contacts S1, S2 and S3.........................448-9. Settings for the process alarm function .........................458-10. Settings for ptoportional control ..................................458-11. Reference temperature ...............................................478-12. Auto return..................................................................478-13. Signalling of FAIL condition .........................................488-14. Temperature sensor and cable length adjustment .......48

8-15. Temperature compensation coefficient adjustment .....498-16. Polarisation check.......................................................508-17. Percent by weight indication on the second display line508-18. Timer on contact function............................................518-19. Settings for the temperature hysteresis .......................518-20. Setpoint setting on maintenance level .........................518-21. Selection of standard electrolytes................................528-22. Fail status signalling ....................................................538-22a. Enable/disable E6 function ........................................538-23. Passcode protection by three digit code .....................548-24. Restore default settings...............................................54

9. RESISTIVITY MEASUREMENT .........................................559-1. Conversion from conductivity to resistivity measurement559-2. Resistivity operation ......................................................559-3. Resistivity default values ...............................................559-4. Resistivity temperature compensation coefficient ..........559-5. Resistivity calibration solutions ......................................55

APPENDIX: SOFTWARE VERSION 2.0 COMPARED WITH 1. * ...............561. Change alarm setpoints from front panel ...............................562. Time-out function on alarm....................................................563. Allocation of alarm contact to temperature ............................564. Selection of ‘Soft’ or ‘Hard’ signalling ....................................565. Matrix temperature compensation .........................................56

SPARE PARTS ........................................................................57

EXPLODED VIEW....................................................................58

IM 12D7C2-01E-H

1

1. INTRODUCTION

1-1. ApplicationThe EXA SC400 mains powered converter isan instrument intended to be used in indus-trial outdoor or indoor installations. It has fullrain and dust protection even during mainte-nance and its small housing makes it theideal instrument for replacements in the fieldor in existing panels. For best results thesensors should be located in the vincity ofthe converter.The power supply can be from most AC orDC sources. The four separate supplyoptions make it a real universal unit. As alloperating parameters are stored in non-volatile memory there is no danger whenpower drops occur. The instrument has awatchdog timer which will always return it tothe normal operating status after power hasbeen removed.The EXA SC400 is compatible with mostcommercially available conductivity sensorsand fitting systems.

The micro-processor in this instrument isused for continuous sensor diagnosis, flexi-ble on site commissioning, advanced outputrelay control functions and fine tuning.

In general a conductivity measuring loopcan be set up for a number of different pur-poses:- To be part of a total process control sys-

tem.- To indicate dangerous limits of a process.- To monitor water quality.- To control the concentration of diluted

chemicals.- To detect the regeneration cycle in demi-

neralisation plants.- To control dosing of nutrient salts in green-

houses.

1-2. Required component for conducti-vity measurement

1. A condutivity sensor (also called conduc-tivity cell) with integral temperature sen-sor (Ni100, Pt100 or Pt1000).

2. A fitting for the above sensor with acces-sories.

3. A signal cable running from the sensor tothe converter with or without extensioncable and connection box.

4. TheEXA SC400 converter with optionaluniversal mounting brackets.

5. An AC or DC power supply.6. Peripherals: e.g. strip-chart recorder, PID

controller.7. Visual or audible alarm devices.8. Equipment to be used for dosing or flow

control like pumps or valves.

2. TECHNICAL SPECIFICATIONS

2-1. General technical specificationsA. Submittals : CSA certificate number 98498,

Class 363101To the requirements C22.2No. 231-M89; ECN 650

B. Measuring rangeConductivity : 2 µS/cm to 500 mSxC for cell-constants

between 0,001 und 50 cm-1

Temperature -10 to 200°C (14 to 392°F) when usinga Pt100-temperature sensor -10 to250°C (14 to 482°F).

C. Transmission signals : - 0-20 mA DC or 4-20 mA DC;isolatedfrom input but not from Voltage signal;maximum loasd 600 Ω

- 0-1 V, isolated from input but not frommA signal; minimum load 1 kΩ

D. Transmission range : - Both signals are user programmable wit-hin hte measuring range of conductivityand temperature (°C/°F) with a minimumspan of 50°C/°F respectively. A 60%zero suppression is the

maximum accepted.- Both signals can be held (fixed or last

value) during maintenace (e.g. calibra-tion).

E. Contact Outputs1. General : - All contacts are ptential-free SPST con-

tacts.- LED indicators for all contact (LED is on

if the contact is closed and power is on).- Switch capacity:

250 V AC, 5 A, max. 100 W250 V DC, 5 A, max. 50 W

2. Alarms : 3 independent process or control alarm(can be programmed by the user).

– Status : High or low process alarm.– Alarm : - Process alarm with adjustable hysteresis

and delay time.- Proportional duty cycle control with

adjustable proportional range, pluseperiod and fixed minimum/maximumduty cycle e.g. for a solenoid valve.

- Proportional frequency control with adju-stable proportional range and pulse fre-quency e.g. for a dosing pump.

3. Fail contact status : Signalling a fault of the measuring loop.

F. Remote range switch : - - Suitable for a remote potential-freecontact switching the measuring rangeto ten times the programmed range.

- Contact open: if impedance > 100 kΩ: Range 1.

- Contact closed: if im pedance < 10Ω: Range 2 (10 x Range 1).

2

IM 12D7C2-01E-H

µS/cm

10.000.0001.000.000

100.00010.000

1.000100

101

0,10,01

Measuring range (related to cell constant)

2-Electrode measurement4-Electrode (advised)Not possible

Cell constant (cm-1)

IM 12D7C2-01E-H

3

G. – Power supply voltage : 110 V AC (±20%), 50/60 Hz.220 V AC (±20%), 50/60 Hz.024 V AC (±20%), 50/60 Hz.024 V DC (±20%/-30%).

– Consumption : max. 8,5 VA– Keys : YES, NO, /\, >, ENT– LEDs : Signalling the relay status.

H. – Display– Type : Custom Liquid Crystal Display.– Main display : 3,5 digits, 12,5 mm high.– Message display : 6 alpha-numeric characters; 7 mm high.– Flags : HOLD, FAIL.– Units : mS/cm, mS/cm or kΩcm, MΩ cm.

I Keys : - 6 keys operated through flexible win-dow with tactile feed-back.

- 1 access key gidden begind the frontcover.

J. Housing– Body material : Cast aluminium with chemical resistant

coating.– Window : Flexible poly-carbonate.– Colours : Moss green / off-white.– Cable glands : 5 polyamide glands PG 13,5.– Terminals : For maximum 2,5 mm2 cable.

K. Mounting Possibilities : - Universal mounting kit is available asan option for panel, wall or pipe moun-ting.

- Suitable for standard DIN sized panels(144 x 144 m).

L. Shipping Details– Dimensions : 144 x 144 x 132 mm– Package : 225 x 225 x 220 mm– Weight : approximately 2,5 kg

M. Safety and Security– Data backup : All data is stored 3 times.– Watch-dog timer : Checking the microprocessor.– Automatice safeguard: Return to measurement when no key is

pushed for 20 minutes.– Interference test : - EMI Class B

- RHF-less than 2% at 5 V/m for 20MHz to 1 GHz, both test accordingto IEC 801.

– Power down : No effect, reset to measurement.– Operation level : Protected by a 3 digit passcode.

2-2. Functional specificationsA. Input specification : Two or four electrodes impedance

measurement with square wave exci-tation.

B. Detection method : Frequency, read-pulse position andreference voltage are dynamically opti-mised.

C. Temperature measurement : Ni100, Pt100 or Pt1000.

D. Temperature compensation : Automatic between -10 to +250°C

(14 to 482°F).

E. compensation algorithm: According to NaCl tables, non-linear

correction for pure water and concen-trated solutions (IEC-746-3 tables).Manually set linear compensation fac-tor.

Model Suffix Code Option Code Description

SC400 ...............................................Microprocessor converterfor conductivity

-C ....................................Always C

-E ................................. European version-U................................. American version-J ................................. Japanese version

Supply- -1............................... 110 V AC 50/60 Hz-2............................... 220 V AC 50/60 Hz-3............................... 024 V AC 50/60 Hz-4............................... 024 V DC

Instruction E......................... English version *

Manual

Options /U ................ Pipe and wall mounting kit/PM ............. Panel mounting kit/Q ................ Quality certificate

F. Performance:

Display 2 1 digitsOutput 0,02 0,02 mA

1 1 mV

Temp. read-outwith Pt100 2 0,1 °Cwith Pt1000 0,2 0,1 °C

Temp. comp.with Pt100 2 0,1 °Cwith Pt1000 0,2 0,1 °C

Signal optimisation takes place by automatic switching of 4 ranges.

2-3. Environmental conditionsA. Ambient operating temperature

: -10 to +55°C (10 to 130 °F)Excursions to -30 ºC (-20 ºF) do notinfluence the current output function,and excursions to +70 ºC (160 ºF) areacceptable too.

B. Humidity : 10 to 90% relative humidity, non con-densing.

C. Weather protection : IP 65 (NEMA 4X), rain and dust-tight.

4

IM 12D7C2-01E-H

ACTION S1, S2, S3 FAIL LEDPower OFF

Power ONNo Alarm

Power ONAlarm

2-4. Model specification

ACCURACY LINEARITY UNITS

Range 1 Range 2 Range 3 Range 4

200 µS 2mS 20 mS

– Response time : 1 to 2 s for 90% of one range.– Range switching : 1 s per range.

*

D. Data protection : Non-volatile memory (EEPROM)

E. Power supply : Max. 50 ms interruption

F. Kontaktaktion :

* Other languages on request. Please contact your local sales organisation.

IM 12D7C2-01E-H

5

2-5. Functional descriptionThe EXA SC400 is a real time micro-control-ler operated conductivity analysing system.It used a dedicated micro-controller withexclusively developed software to control allfunctions necessary in such a system. Theinput and output functions are concentratedin the analogue section of the instrument.Even these functions are operated throughspecial interfaces designed to give a mini-mum of interference problems to the digitalfunctions. The digital and logic functions,including the energizing of the output relays,are designed to operate securely.

The output contacts are voltage-free relaycontacts which can be used as processalarms or to control a process. The EXAgives you three pre-defined process alarms(one high, one low, on inactive) and a FAIL-contact. All contacts are signalled on thefront by LED’s.The unique FAIL-contact gives a warningwhen the micro-controller has found a faultin the measuring loop. By fine-tuning thecontacts can be used for simple proportion-al control.

The micro-controller checks the working ofthe analogue to digital input converter circuitand watches over the conversion to the out-put signals. By using non-volatile memory(EEPROM) for the essential infromation theoperating parameters are fixed in memorywithout the need for a battery.The software is desighned with the user inmind. It uses a simple step by step,question and answer style to communictewith the operator by giving messages on thesecond line of the display nd indicatingwhich keys are to be pressed in the displaytoo.The user-interface is simplified to a basic setof 6 keys accessible through the flexiblewindow cover. The dys are scanned conti-nuously and actions are taken immediately.An extensive systme of checking values andparameters is implemeted in the software.

The converter can be pwered from AC orDC supply voltages. The AC voltages havewide tolerances (±20%) e.g. the 220 Voltversion can be pwered from sourcesbetween 176 and 264 VAC at 50 or 60 Hz.The 24 Volt DC version is included to enableuse in mobile or battery powered installa-tions.

The rugged housing is designed for outdooruse (IP65). In addition it is shaped in a waythat the indooor panel mounting is also pos-sible (DIN size 144 x 144 mm). The optionaluniversal mounting brackets are used for allmounting methods.

The commissioning of the instrument can beperformed on site or in advance. A threelevel operating system keeps the approachclear and distinguishes between every dayoperation and maintenance against one timeoperations like commisioning or fine-tuning.All this makes the EXA SC400 operate like anormal analogue converter with a number ofadditional functions. These extra functionsare only possible by ussing a micro-control-ler at the heart of the system.- Simple range adaptation making it a versa-

tile instrument.- Zero suppression up to 60% of end scale

value.- Continuous sensor polarisation check

during measurement.- 2 or 4 electrode measuring principle can

be selected.- Output table can be programmed in 21

steps. - Accurate temperature compensation by

non-linear NaCl algorithm.- Automatic optimum adaptation of measu-

ring pulse, frequency and reference volta-ge.

- Dual analogue output signals: mA and V.- Output contacts for alarming or process

control.- Remote range switch to give a tenfold

range.- A HOLD function for the outputs.- Protection against unauthorized access to

the Maintenance, Commissioning orService level by a passcode.

6

IM 12D7C2-01D-H

IM 12D7C2-01E-H

7

138(5.43)

138(5.43) M5

M6

M6 144(5.67)

24(1)

115.5(4.55)

16.5(0.65)

MINIMUM185(7.25)

MINIMUM195(7.75)

144(5.67)

3.INSTALLATION AND WIRING

3-1. Installation and dimensions

3-1-1. Installation siteAs the converter is a rain-tight type, it can be installedoutdoors as well as indoors. It should, however, be instal-led as close as possible to the sensors to avoid longcable length between the sensor and the transmitter.Select an installation site where:- mechanical vibrations and shocks are negligible;- no relay or power switches are in the direct environ-

ment;- the converter is not exposed to direct sunlight or severe

weather conditions;- maintenance activities are possible (no corrosive

atmosphere).The ambient temperature and humidity should be withinthe limits of the specifications.

3-1-2 Mounting methodsThe EXA SC400 converter has universal mounting possi-bilties:- panel mounting using the optional brackets;- wall mounting using the optional brackets.

First the brackets are fixed to the housing. Then it ispossible to put fixing screws through the bracket in thewall.

- Pipe mounting using the two optional brackets, on ahorizontal or vertical pipe (diameter 40 to 70 mm).

The following drawings show these mounting methods indetail.

PANEL MOUNTING DIMENSIONS Unit : mm (inch)

PANEL CUT-OUT AND SPACING

CUT-OUT = 138x138 (5.43 x 4.53)

Figure 1.

8

IM 12D7C2-01E-H

UNIVERSAL PIPE/WALL MOUNTING WALL MOUNTING

PIPE MOUNTING

Wall mount

Pipe mount(vertical)

Pipe mount(horizontal)

2” I.D. pipe

Figure 2.

200(7.87)

70(2.75)

144(5.67)

145(5.71)

Unit: mm

IM 12D7C2-01E-H

9

3-2. System configuration

POWER

OUTPUT SIGNALS

CELL

CONTACT INPUTCONTACT OUTPUT

RANGE SWITCH

* Fail safe action (closed when power is off)

FAIL

Figure 3.

10

IM 12D7C2-01E-H

3-3.Wiring

3-3-1. PreparationThe procedure for opening the EXA SC400is described in the most convenient way. Ifconnections are made to the contact out-puts or power terminals the screening platemust be removed. As the input terminals arelocated over the output contact terminals, itis not easy to connect wiring to them withthe input cables in place.

Therefore we recommend to use the follo-wing sequence (see fig. 4a and 4b):1. Remove the cover of the EXA SC400 by

loosening the 4 captive screws.2. Swing the display board to the left like a

door.3. The upper terminal stirp is now visible.

Remove the screen plte covering thelower terminal strip.

4. Start by connecting the power and con-tact outputs. See the instructions in §3-4.Use the three glands at the back to guidethe cables out (see fig. 4b and fig. 5).

5. Replace the screen plate over the lowerterminals.

Always replace the screen plate overthe power and contact outputs toavoid interference.

6. Connect the analog output and sensorinput cabling. See the instructions in §3-3-4 and §3-3-5 using the two glands atthe front (see fig. 5 and fig. 7).

7. Swing back the display board and switchon the power. Commission the instru-ment to your needs or use the defaultsettings.

8. Close the instrument by refitting thecover.

Screws(4)

Gasket Cover

HingeFront(see inside cover)

Hidden key andmenu

Window

Fig. 4a.

IM 12D7C2-01E-H

11

Digital board with LCDand keys

Parameterswitch

Analogue in and outputterminal

Power and contact output terminalcovered by screen plate

Glands (5)

Fig. 4b.

12

IM 12D7C2-01E-H

Fig. 5. Glands to be used for cabling

Fig. 6. Grounding

Fig. 7 Glands

Power supplycable

Analogueoutputscable

Contact (S1,S2) output

cable

Sensorcable(s)

Contact (S3,S4, Fail) out-

put cable

Communi-cation,

contakt-input

IM 12D7C2-01E-H

13

3-3-2. Wiring of power supply

3-3-2-1. General precautionsDo not activate the power supply yet. Firstmake sure that the power supply is accor-ding to the specifications given. Remove thefront cover by unscrewing the 4 captivescrews. Then check the type-plate on theinstrument for the correct supply voltage.

Local regulations may ask for an externalcircuit breaker to be installed. The instru-ment is protected internally by a fuse withthe following ranges:220 VAC - 63 mA, 24 VAC - 0.5 A110 VAC - 100 mA, 24 VDC - 1.0 AThe internal fuse is located net to the powerterminals.

3-3-2-2. Access to terminal and cableentry

The terminals 1, 2 and 3 from the bottomstrip are used for the power supply. Guidethe power cable through the nearest gland.The terminals accept wires of 2.5 mm2

maximum. Use cable finishings if possible.Connect the wires as indicated in the wiringdiagram (fig. 8).Connect terminal 1 to the phase line of theAC power and terminal 2 to the zero line.For DC power terminal 1 should be connec-ted to the positive outlet and terminal 2 tothe negative outlet (see fig. 8).Terminal 3 is for the power ground. This isseparated from input ground by a galvanicisolation.

3-3-3. Switching on the instrumentAfter all connections are made and chec-ked, the power can be switched on from thepower supply. Observe the correct activa-tion of the instrument at the display. Afterlighting all segments the EXA SC400 willdisply a value. If errors are displayed or avalid conductivity value is not shown, con-sult the trouble shooting section §7-1 beforecalling Yokogawa.

3-3-2-3. Grounding the housing(see fig. 6)To protect the instrument against interferen-ce the housing should be connected toground by a large area conductor. Thiscable can be fixed to the back side of thehousing using a braided wire cable with alug. Put a (serrated) lock washer under thelug to improve the contact to the housing.

1 2 3

Phase 0+ -

Fig. 8 Power supply

3-3-4. Wiring the contact signals

3-3-4-1. General precautionsThe contact output signals consists of volta-ge-free relay contacts for switching electricalappliances (SPST). They can also be usedas digital outputs to signal processingequipment (e.g. PLC).The only contact input is for a remote swit-ching of the range.

It is possible to use multi-core cables for thecontact in- and output signals and screenedmulti-core cable for the analogue signals.

14

IM 12D7C2-01E-H

3-3-4-2. Contact outputsThe 4 contact outputs can be wired afteryour own preferences. All contacts are open when power is on andno alarm or control is functioning. The FAILcontact closes when power is off.You can either use them to switch ACpower, to switch a DC voltage for digitalinterfacing.

The first contact (S1) is pre-programmed fora high alarm function.The second contact (S2) is pre-programmedfor a low alarm function.The third contact (S3) is not activated as analarm.These contacts can be used for simple pro-cess control by programming their functionin §8-8.

The FAIL contact is programmed to signal afault in the measuring loop.Always connect the FAIL-contact to analarm device (e.g. lamp, signal horn, alarmpanel) to make use of the fault detectionpossibilities of the EXA transmitter.

Note: The status of the contacts can bechanged form NO to NC by changingthe (soldered) jumpers (see fig. 10) onthe power supply board.

3-3-4-3. Contact imput for range swit-ching

The terminals numbered 21 and 22 areused to connect a switch. When this switchis closed the range is switched to a ten-foldrange.The switch should be closed as long as youwant this ten-fold range. Switch back byopening the contact again.

3-3-5. Wiring the analogue output sig-nals

3-3-5-1. General precautionsThe analogue output signals of the EXASC400 transmits low power standard indus-try signals to peripherals like control sys-tems or strip-chart recorders.

3-3-5-2. Analogue output signalsThe first output signal consists of an activecurrent signal of either 0..20 or 4..20 mA.The maximum load can be 600Ω.The second output signal consists of a vol-tage signal fo 0..a V.The input impedance of the receiving instru-ment should be more than 1 kΩ.It is highly recommended to use shielding onthe output signal cables. Terminal 63 isused to connect the shielding.

SpannungAUS

Spannung EINKein Alarm

Spannung EINAlarm

FAIL

Abbildung 9.

Fig. 10

Abbildung 11.S1, S2, S3Action

21 22

S1 S2 S3 S4

NC

IM 12D7C2-01E-H

15

3-3-6. Wiring of sensors

3-3-6-1. General precautionsGernerally, transmission of signals from theconcuctivity sensor is a low voltage AC sign-al. Thus care must be taken to avoid interfe-rence. Refer to section 7-2 for sensor selec-tion criteria.Before connecting the sensor cable to thetansmitter make sure the next conditions aremet:- the sensor cables are not mounted in

tracks together with high voltage and orpower switching cables;

- only standard conductivity cable or exten-sion cable are used;

- the transmitter is mounted within the dis-tance of the cable (maximum length forstandard conductivity cables is 10 m). Fora larger distance use extension cable andconnection box as dexcribed in §3-5-2;

- the fixing of cables is dept flexible for eayinsertion and retraction of the sensor in thefitting.

3-3-6-2. Using an extension cable andbox

If the distance between sensor and trans-mitter is more than 10 meters (the length ofstandard conductivity cable), an extensioncable and connection box should be used.Yokogawa delivers special extension cabletype WF10 and a metal connection box typeBA10 for this purpose.

Do not use more than a 50 meter extensioncable for interference reasons. Conductivitycables of 15, 20 or 30 meter length can beordered as a special request.

3-3-6-3. Liquid earthThe sensor side of the measuring loop isgrounded to the measuring liquid. The EXASC400 uses advanced high impedanceinput circuits.In addition to that the polarisation checkingis depending on cable impedance.

Fig. 12. Wiring diagram

Temperaturesensor

Temperaturesensor

Cellelectrodes

Cellelectrodes

2-Electrode-system

4-Electrode-system

Fig. 13

31 32 41 42 51 52 71 72

S1 S2 S3 FAIL

61 62 65 66 63

+ mA - + mV -

11 12 13 14 15 16

t

11 12 13 14 15 16

t

16

IM 12D7C2-01E-H

4. START-UP

4-1. GeneralThe EXA SC400 converter has one hardwa-re version for a multiple of different applica-tions so that it offers extreme flexibility to theuser.The software has been set for a ‘generalapplication’. Some easy programming willfingerprint the converter to the particularapplication.Programming is easy. However, a good per-paration is necessary and this chapter willassist the user in recognising the superbflexibility of the converter and getting themost out of it.

4-2. The DISPLAY functionsThe EXA SC400 converter features acustum made display which enables to readthe selected value of the sensors (see insidecover).

4-2-1. The primary displayThe primary display indicates the measuredvalue.The primary display is also used to displaythe variables that can be adjusted in the dif-ferent programming steps. Generally, theSHIFT (>) key changes the position of thedigit that can be set with the UP (^) key. Thedigit is flashing together with the correspon-ding flags.When PERIOD (.) is flashing the UP key willmultiply the value by a factor of 10.

Notes:1. When the ‘adjustment keys’ flag is flas-

hing and no digit is flashing, then the UPkey will present either - or 1 in front of the3 digits shown.

2. The display indicates conductivity valuesin either µS/cm or mS/cm. When PERIODis flashing the unit will change automati-cally after pressing the UP key.Make sure that the correct unit is indica-ted during range adjustments.

4-2-2. The secondary displayThe secondary or MESSAGE display willindicate error codes after a fail situation.During START-UP this can be the result ofincorrect connection of sensor wiring (E5 orE6), dry cell (E6) or the use of a sensor witha temperature sensor different from the pro-grammed one (E7 or E8).

Normally, the message display indicates theprocess temperature. This can be changedby the user into an indication that is moreimportant for the application (see §5-2).Indication can be:1. Temperature2. mA output3. Percent by weight4. Calibrated cell constant5. Reference temperature6. Temperature coefficient7. Software release version

4-2-3. AnnunciatorsThe custom made display will also indicaterelevant messages. An arrow points themeasuring or programming mode.HOLD indicates a frozen output (see sec-tions 5-3 and 6-3).

4-3. The output functionsThe EXA SC400 has an isolated current out-put (default value: 4-20 mA) and a voltageoutput (0..1 V). The output current can bechanged to 0-20mA (see service code 4).The outputs represent the measured con-ductivity value.Other allocations can be made in servicecode 7.The range can be set in the commissioningmode (see section 6-2).

The output is linear to the measured value. Ifa different I/O function is required entering ofa 21 point table can be achieved (see servi-ce code 5/6).

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17

4-4. The contact output functionsThe default of the contacts S1 and S2 is setas high and low alarm for the conductivityvalue.Contact S3 is not activated.

To change the allocations of the contacts,refer to service codes 08 and 09.

To change the characteristics of the con-tacts, reger to service codes 11-14 and, ifproportional control functions are required,to service codes 15-17.

4-5. The temperature compensationfunctions

The EXA SC400 is set for temperature com-pensation of NaCl solutions according toIEC 476-3 standards. If the temperaturecoefficient is known (see service code 19) itis possible to change to a linear temperaturecompensation. Compensation for NaClmust then be switched off (see section 6-4).In this section also a description is givenhow to enter an empirical field calibration ofthe coeffient.

It is also possible to use a pre-programmedmatrix compensation for more complicatedsolutions (ultra pure water, cation conducti-vity measurement, etc.). This can be selec-ted in service code 25.

4-6. The sensor characteristicsThe EXA SC400 is based on the use of aconductivity sensor with a cell constant of0.1/cm and a Pt1000 RTD temperaturecompensating element. The cell constantcan be changed (see service code 02).Changing of the temperature compensatingelement can be in service code 01.

4-7. CalibrationThe sensors of YOKOGAWA have calibratednominal values which correspond with thevalues entered in service cod 02. It is possi-ble to fine tune the converter by doing agrab sample calibration (see section 5-1).

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4-8. Operations overview

MAINTENANCEOperation by keys through theclosed cover

CAL

DISPLAY

HOLD

Calibration

Show or fix additional values

Switch hold function on/off

5-1

5-2

5-3

Adjusting the setpoints fort the output contacts

Adjusting the output range

Activating the hold function

Temperature compensation adjustment

6-2

6-3

6-4

6-5

Fine tuning the performance 8

SETPOINTS

RANGE

SET HOLD

TEMP

SERVICE

COMMISSIONINGOperation by *-key when coveris removed

SERVICEOperation by coded entry fromcommissioning

Routine Use Chapter

NOTE: All 3 levels can be seperately protected by a passcode. See §8-23.

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19

5. MAINTENANCE

IM 12D7C2-01E-H

START = Start calibration NOTE:If calibration is out of limits (+/- 20 % of Nom.C.C.), “ERROR 3” will appear in the display. To continue press YES or NO, “Cal. C.C.” willbe shown on the display.

Press YES to calibrate the cell constant (newcell constant is calculated and updated).

Press NO to stop calibration of the cell constant (no update of cell constant).

20

5-1. Calibration

1. Access to calibration routine 2. Adjust value 3. End calibration

M E A S U R EC A LD I S P L AY.H O L D

YES NO

YES NO

MODE

µS/cm


YES NO

YES NO

MODE

µS/cm


YES NO

YES NO

MODE

µS/cm

Press MODE-key for access tomaintenace mode.=

Select digit to adjust

Adjust value

Confirm adjusted value

Stop calibration

ENT

LPress NO-key until the displayindicates CALIB

NO

NO

LCalibration is finished after pres-sing YES-key. Return to measringmodeBy pressing NO-key there is a re-start (step 2)

YES

NO

ESCAPE TO MEASUREMENT can be used at any stage to abort operation. WARNING: If the HOLD function is activated the instrument returns with the question HOLD (flas-hing); answer YES or NO or MODE again to return to measurement.MODE

MODE

Select calibration routine

Confirm selection by pressingYES-key. the display will indicateSTART

YES

Confirm start of adjustment by pres-sing YES-key

YES

CALIB = Calibration

Adjust process value to a previously deter-mined value (e.g. taken from a hand-heldconductivity meter)

CAL.END = End of calibration session

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21

1. When is calibration necessary?Calibration fo conductivity instruments isnormally not required, since conductivitycells are manufactured within controlledtolerances and will not alter in use. In §8-2the cell constant can be programmed.

If the cell has been severly fouled or subjec-ted to abrasion (possibly during incorrectcleaning) it may be necessary to calibrate.

Alternatively calibration may be carried outwith a simulator to check the electronicsonly.

2. How is calibration done?Calibration is carried out by measuring asloution which has known conductivity at aknown temperature and adjusting the instru-ment to show the correct conductivity value.

Calibration solutions can be made up in thelaboratory. An amount of salt is dissolved inwater to give a precise concentration. Thetemperature is stabilised tothe referencetemperature of the instrument (usually 250C).The conductivity of the solution is takenfrom literature tables or the table on thispage.

Alternatively the instrument may be calibra-ted in an unspecified solution against astandard instrument. Here care should betaken to make the measurement at the refe-rence temperture since differences in thetype of temperature compensation of theinstrument may cause an error.

3. Typical calibration solutionsThe tabel below shows some typical con-ductivity values for sodium-chloride (NaCl)solutions which can be made up in the labo-ratory.

5-1.Calibration

% weight mg/kg Conductivity

00.001 10 021.40 µS/cm00.003 30 064.00 µS/cm00.005 50 106.00 µS/cm00.01 100 210.00 µS/cm00.03 300 617.00 µS/cm00.05 500 001.03 mS/cm00.1 1000 001.99 mS/cm00.3 3000 005.69 mS/cm00.5 5000 009.48 mS/cm01 10000 017.60 mS/cm03 30000 048.60 mS/cm05 50000 081.00 mS/cm10 100000 140.00 mS/cm

Table for NaCl at 25°C

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22

The second line of the display will show thepossibilities

5-2. Selecting a value to display

1. Access to display routine


YES NO

YES NO

MODE


YES NO

YES NO

MODE


YES NO

YES NO

MODE

Press MODE-key for access tomaintenance mode

Press this key until DISP is indica-ted

NO

MODE

Select display routine

Confirm selection by pressingYES-key. The display will indicatethe selected parameter

YES

DISP = Display-Routine

By pressing the NO-key the dis-play will indicate the parametersto be selected

Parameter Unit- Temperature ˚C/˚F- Output signal mA/V- % by weight %

C.C - Cell constant cm-1

T.R. - Reference temperature ˚C/˚F

NaCl/jjj - TemperatureCompensations coefficientstandard/manually set %/˚C

REL - Software release

Return to measurement mode bypressing MODE-key

NO

MODE

Reprogram data display Move to desired parameter to display

Parameter Unit- Temperature ˚C/˚F- Output signal mA/V- % by weight %

C.C - Cell constant cm-1

T.R. - Reference temperature ˚C/˚F

NaCl/jjj - TemperatureCompensations coefficientstandard/manually set %/˚C

REL - Software release

Confirm selection for permanentdisplay during measurment

NO

YES

ESCAPE TO MEASUREMENT can be used at any stage to abort operation. WARNING: If the HOLD function is activated the instrument return with the question HOLD (flas-hing); answer YES or NO or MODE again to return to measurement.MODE

1. Read data 1. Reprogram data display

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1. What is the display routine?The second line in the display is intended tobe used to:- Show actual status- Show messages- Show errors

When delivered from the factory the EXASC400 shows the temperature on thesecond line.

You can make the instrument show a diffe-rent parameter on the second line by selec-ting it from the list at right.

2. What can you read?Temperature is an actual value.Output is an actual value.Percent by weight is an actual value.Cell constant is programmed.Reference temperature is programmed.NaCl ortemperature coefficient is programmed.

The choice of temperature units is donefrom the Service level.

Error messages have priority over othermessages.

NOTE: Percent by weight si only visible when acti-vated from the service level §8-17. In caseof FAIL-status and Error code E7 or E8 thetemperature read-out in the DISPLAY-routi-ne shows T.HIGH resp. T.LOW (refer to section 7).

3. ExampleTo check the value of the output signal(4...20 mA) it is displayed on the secondline.

Measuring range 0...100 µS/cmOutput signal 4...20 mA

Process value 60 µS/cmOutput value 3,6 mA

When the second line is changed to displayoutput the current signal is visible all thetime.

Whenever HOLD is activated the value onthe display is frozen to the programmedvalue (using the FIXED setting).

Pressing MODE will take you back tomeasuring and the temperature will showagain.

5-2. Selecting a value to display

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24

NOTE: This function can only be used if acti-vated during commissioning (see §6-3).

Make selection the switch HOLD on or off

5-3. HOLD output function

1. Access to HOLD routine


YES NO

YES NO

MODE


YES NO

YES NO

MODE

HOLD

Press MODE-key for access tomaintenance mode

Press this key until the displayindicates HOLD

NO

MODE

Select HOLD-routine

Confirm selection by pressingYES-key. Display will blink bothHOLD and YES/NO

YES

HOLD = Hold output function

Switch hold OFF by pressing NO-key

NO

Switch hold ON by pressing YES-key

YES

HOLD in the left top corner of the display isindicated.If HOLD is ON alarms and control cannot beactivated.

ESCAPE TO MEASUREMENT can be used at any stage to abort operation. WARNING: If the HOLD function is activated the instrument returns with the question HOLD (fla-sing); answer YES or NO or MODE again to return to measurement.MODE

2. Switch HOLD on/off

IM 12D7C2-01E-H

25

1. What is HOLD?Hold is a function which freezes the outputsignal temporarily, it is normally used duringmaintenance when the cell is removed fromthe measured solution to prevent unwantedcontroller reaction.

The HOLD function must be commissionedfrom the programming menu before it canbe switched on or off. See commissioningthe hold function for more details §6-3.

2. How does it work?From this level the HOLD function can onlybe switched ON or OFF.

HOLD is switched on when you press YESwhen HOLD and YES/NO are blinking.When you press NO hold will be switchedoff.

A flag is kept in memory and an indication ismade in the upper left corner of the displayfield.

The HOLD function influences the outputsignals (mA and V), the alarm of controlfunctions and the FAIL-contact.

The operator is prompted to switch HOLDon or off after having performed a mainte-nace or commissioning function.

3. ExampleDuring the transfer of cleaning liquid into abatch reactor with a conductivity-controlsystem, the HOLD function is switched ONto prevent the controlling instrument fromrunning wild.

After cleaning has ceased and the newbatch has been started HOLD is switchedOFF again and conductivity control resu-mes.

5-3. HOLD output function

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26

Remove cover by releasing 4 screws Display will show * SETP1 The display indicates the actual setting inengineering units. This setting can be chan-ged using keys:

6. COMMISSIONING

6-1. Adjusting the setpoints

1. Access to setpoints menu 2. Select which setpoint to adjust

S E T P O I N T SR A N G ES E T H O L DT E M PS E R V I C E

YES NO

YES NO

MODE


YES NO

YES NO

MODE


YES NO MODE

mS/cm

ENT

Press YES-key to adjustsetpoint S1 or press NO-key to change to setpoint S2 and after

that YES-key

YES

NO

ESCAPE TO MEASUREMENT can be used at any stage to abort operation. WARNING: If the HOLD function is activated the instument return with the question HOLD (flashing):answer YES or NO or MODE again to return to measurement.MODE

Press this key until SETP is indi-cated

Press this key for access to com-missioning mode

NO

Select setpoints menu for contact outputs

Confirm selection by pressingYES-key. Display indicates SETP1

YES

SETP = Setpoints menu

*

NOTE: If none of the contact outputs is acti-vated, this item will be skipped.

The message display will indicate the parame-ter to which the contact is allocated SC (con-ductivity) or ToC/ToF temperature.

NOTE: SETP1 is for the contact ouput marked S1 and is pro-grammed as a high alarm for conductivity (default).SETP2 is for the contact ouput marked. S2 and isprogrmmed as a low alarm for conductivity (default).SETP3 for S3 is not activated.To change the funcitoning of output contacts refer to§8-8 & §8-9.


Adjust digit

Enter adjusted value

Return to measurement mode

ENT

L

MODE

L

3. Adjust the setpoint value

SETP1 is default at 1 mS/cmSETP2 is default at 10 µs/cm

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27

1. What are setpoints?In general the contact outputs of the EXASC400 can be used to signal extraordinarysituations in the process.The alarm contacts are switched if the com-parison of the changing process value to afixed setpoint meets the condition of thealarm function (higher or lower). These set-points are programmed in this section.

One of the advantages of a micro-processorinstrument is, that it is fairly simple to changethe function of the contact outputs. It is pos-sible to use the contact for simple processcontrol functions like proportional duty cycleor pulse frequency control.The adjustment of the setpoints for thesecontrol functions also has access from thissection.The setting of the control type and parame-ters have access through the service level at§8-8.The function of the FAIL-contact cannot bechanged. It is signalling faults in the measu-ring loop to e.g. a connected control panel orcontrol room. It is recommended to alwaysconnect the FAIL-contact because it over-rules all other signals from the EXA SC400. Inaddition it is possible to activate a special 22mA and 1100 mV signal on the output whenFAIL is on (see §8-13).

2. How does it work?As an example we will describe what hap-pens when the process value exceeds thehigh alarm setpoint of S1.

When the process value rises above the set-point of S1, the delay time of the relay con-tact starts. After the delay time has passedthe LED lights and the relay contact isswitched on.When the process value goes down again,the value must be below the setpoint minusthe hysteresis. After the delay time has expi-red the LED and the relay are switched off.

The hysteresis (sometimes called ‘dead-band’) and the delay time are programmedfrom the service level at §8-9 for conductivityand at §8-19 for contacts allocated to tempe-rature.These parameters are intended to mask theeffects of sudden peaks in the process valueand the mechanical characteristics of sole-noids.The hysteresis works on one side of the set-point only. For a high alarm it is below thesetpoint; for a low alarm it is above the set-point.

3. Process control with output contactsThe EXA SC400 incorporates simple processcontrol functions. A differentiation is madebetween 3 kinds of control functions:- on/off control with the alarm function- proportional duty cycle control

- proportional pulse frequency control.

In the first case the programmable setpoint,hysteresis and delay time of the alarms giveyou the possibility to set up a simple controlfunction.The proportional duty cycle control has aprogrammable pulse period and a propor-tionally chnaging duty cycle. The proportion-al control range and pulse frequency controlchanges the number of pulses between 0and the programmed maximum. The pulseduration is fixed to 0.3 seconds. The pro-portional control range and maximum num-ber of pulses must be set in §8-10.As all settings are in percent of proportionalcontrol range the actual linear or non-linearbehaviour through an output table has noinfluence on the functioning of the alarm orcontrol functions.

4. Special featuresAdjusting the setpoints can be done withoutopening the instrument. Therefore accessmust be selected in service code 24 (see§8-20).NOTE: The proportional control function is

only applicable for contacts allocatedto conductivity.

6-1. Adjusting the setpoints

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28

6-2. Range adjustment

Remove cover by releasing 4 screws Display will show *0% Display will show *100%

1. Access to range menu


YES NO MODE

YES NOS E T P O I N T SR A N G ES E T H O L DT E M PS E R V I C E

YES NO MODE

ENT

µS/cm


YES NO MODE

ENT

mS/cm

Press NO-key until the displayindicates RANGE

Confirm selection by pressingYES-key. The display indicates0%

NO

YES

Select range menu

Press this key for access to com-missioning mode*

NOTE:If the output is commissioned to be via a table this whole item willbe skipped! Default is a linear range.


Adjust digit

Enter adjusted value. Display indi-cation moves to 100%ENT

LL Select digit to adjust or decimal

points units

Adjust digit



ENT

L

MODE

L

Adjust begin scale value of the span Adjust end scale value of the span


2. Adjust low span value 3. Einstellung des oberen Wertes derSpanne

IM 12D7C2-01D-H

29

1. What is the range?

The display will always show the full range ofthe instrument form 0-2000 mS/cm.Maximum resolution is assured by autoran-ging, where the position of the decimal pointand the measuring units(microSiemens/milliSiemens) are moved tobest fit the actual value.

For control or recording the current outputcan be ranged to a specific part of the totalmeasuring span. When selecting themeasuring range care must be taken to usethe appropriate conductivity cell. For anygiven cell constant there is a defined rangeof operation which should not be exceeded(refer to §2-1).

From the factory the instrument has a linearouput range 0-1 mS/cm in combination witha cell constant C = 0.1 cm-1.

Other linear ranges can be programmed inthis routine. It is also possible to programnon linear output ranges for specific applica-tions. These are programmed in the servicelevel, see sections §8-5 and §8-6.

2. Programming a linear output rangeA linear output range is programmed byentering two values:- 0% the conductivity at the start of the

output range which corresponds to4mA (or 0 mA)

- 100% the conductivity at the end of theoutput range which corresponds to20 mA.

When programming a range which does notstart at zero conductivity, take care torepect the minimum span corresponding to60% of the maximum value.

3. Programming a non-linear rangeThe EXA SC400 has an output table whichcan be programmed to give any non-linearoutput characteristic. Activation of this tableis described in §8-5. Once the table is acti-vated the linear RANGE routine will no lon-ger have any effect and will not be accessi-ble in the commissioning menu.

Programming of the 21 point table is descri-bed in §8-6.

Non-linear ouputs are commonly used formeasurement in pure water where highresolution is required over a small rangecombined with trend indication over a largerrange. Common forms of output for theseapplications are given in §8-6.

The non-linear output can also be used tofollow a concentration curve for a specificproduct. Care must be taken to ensure thatthe temperature compensation is also setup for the measured fluid under representa-tive conditions. It should also be noted thatconductivity measurements are not specific,so it can be influenced by imurities presentor changes in the fluid composition.

4. Other possibilitiesProgramming a percent by weight indicationon the second display line §8-17.

6-2. Range adjustment

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30

6-3. Set up the hold function

Remove cover by releasing 4 screws Display shows actual status*H.OFF = Hold no active*H.ON = Hold activated

1. Access to hold menu


YES NO MODE


YES NO MODE

YES NO

Change status

Confirm selection

NO

YES

Change selection

Confirm selection. The display will indi-cate a mA/mV-value (H.FIX is selected)or return to measurement mode

NO

YES

Display shows current setting*H.FIX = Hold fixed valve*H.LST = Hold last valveSelect Hold fixed or last

*H.mA = Fixed mA-value*H.mV = Fixed mV-value


YES NO MODE

HOLD

ENT

Adjust fixed value



Adjust value

Enter selected value


ENT

L

MODE

L

Press NO-key until the displayindicates HOLD


NO

Select HOLD menu

Confirm selection by pressingYES-key. The display will indicateactual status

YES

* HOLD = HOLD menu

*

Activate (de-activate) HOLD function

2. Activate hold function 3. Select value to hold

IM 12D7C2-01E-H

31

1. What is HOLD?HOLD is a function freezing both output sig-nals temporary, during normal maintenace,preventing all sorts of alarming situations tooccur.

Two possibilities are generally used:

- Keeping the output at the last value(H.LST) just before the start of maintenan-ce. This is the recommended setting whenrecording instruments are connected tothe output signals.

- Keep the output signals at a preset value(H.FIX) which will not cause any action tobe taken by a connected instrument (e.g. aPID-controller). This is the preferred situ-ation when dealing with conductivity con-trol systems.

In both situations the alarm contacts willswitch off and the proportional control (ifactivated) will be disabled. Also the FAIL-contact will be disabled.

2. How does it work?The HOLD-function has to be activated fromthis menu before it can be used.

The EXA SC400 will keep both outputs fro-zen during one of the following events:- Access to the commissioning menu (*-key).- Access to the calibration mode (§5-1).- Switching it from the maintenance menu

(§5-3).

HOLD is signalled in the display by a specialflag.

The operator is prompted to switch HOLDon or off before returning to normal meas-urement when the HOLD function is activa-ted.

3. ExampleIn a storage tank the concentration of sodi-um hydroxide (caustic soda = NaOH) has tobe kept at 5%. The mixing process is con-trolled by an EXA SC400 conductivity trans-mitter and electro-magnetic valves (usingduty cycle control).

During maintenance of the conductivity cellor the transmitter the HOLD function is acti-vated to keep the mixing process from was-ting precious chemicals.

The HOLD function is used to set a fixedvalue for the output to the strip-chart recor-der during maintenance. The control by thetransmitters output contacts is halted duringHOLD.

Afterwards HOLD is de-activated and con-trol resumes.

4. Other possibilitiesHold is de-activated after 20 minutes if nokey is pressed. To de-activate this functionsee §8-12.

6-3. Set up the Hold function

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32

6-4. Temperature compensation

Remove cover by releasing 4 screws NaCl = Standard temperature compensationT.C. = Manually set temperature compen-

sation factorSelect required temperature compensation

1. Access to temperature compensationmenu


YES NO MODE


YES NO

YES NO

MODE

Change selection

Confirm selection by pressingYES-key

NO

YES

NOTE: If NaCl is selected the temperaturecompensation will be according toNaCl solutions (IEC tables).If T.C. is selected a value will be indi-cated in the display.

The temperature compensation coefficientto be set is done by adjusting a conductivityvalue (at process temperature) to the con-ductivity value (at reference temperature).

Adjustment of the temperature compensa-tion coefficient


YES NO MODE

mS/cm

ENT

ESCAPE TO MEASUREMENT can be used at any stage to abort operation. WARNING: If the HOLD function is ctivated the instrument returns with the question HOLD (flas-hing); answer YES or NO or MODE again to return to measurement.MODE


Adjust value

Enter adjusted valueENT

L

LPress NO-key until the displayindicates TEMP


NO

Select temperature compensation menu

Confirm selection by pressingYES-key. The display will indicateactual status

YES

TEMP. = Temperature compensation menu

*

2. Select automatic or manually setcompensation

3. Set the temperature compensationcoefficient (only if T.C. is selected)

IM 12D7C2-01D-H

33

1. Why temperature compensation?

The conductivity of a solution is very depen-dent on temperature. Typically for every 1°Cchange in temperature the solution conduc-tivity will change by approximately 2% Theeffect of temperature varies from one solu-tion to another and is determined by severalfactors like solution composition, comcen-tration and temperature range.A coefficient (α) is introduced to express theamount of temperature influence in % chan-ge in conductivity/°C.In almost all applications this temperatureinfluence must be compensated before theconductivity reading can be interpreted asan accurate measure of concentration orpurity.

NaCl compensation accordingIEC 746-3 with Tref = 25°C

2. Standard temperature compensation

From the factory the EXA SC400 converteris calibrated with a general temperaturecompensation function based on a sodiumchloride salt solution. This is suitable formany applications and is comptible with thecompensation functions of typical laboratoryor portable instruments.

A temperature compensation factor is deri-ved from the following equation:

α =Temperature compensation factor (in %/°C)

T =`Measured temperature (°C)Kt =Conductivity at TTref =Reference temperature (25°C)Kref =Conductivity at Tref

3. Manual temperature compensation

If the standard compensation function isfound to be inaccurate for the sample to bemeasured, the converter can be set manual-ly for a linear factor on site to match theapplication.The procedure is as follows:1. Take a representative sample of the pro-

cess liquid to be measured.2. Heat or cool this sample to the reference

temperature of the converter (usually25°C).

3. Measure the conductivity of the samplewith the EXA SC400 and note the value.

4. Bring the sample to the typical processtemperature (to be measured with theSC400).

5. Adjust the display indication to the notedvalue at the reference temperature.

6. Check that the temperature compensa-tion factor has been changed.

7. Insert the conductivity cell into the pro-cess again.

4. Other possibilities1. Enter calculated coefficient (see §8-15).2. Enter matrix temperature compensation

(see §8-21).

6-4.Temperature compensation

Kt - Kref x 100α = X

T - Tref x Kref

T Kt α T Kt α T Kt α00 0.54 1.8 060 1.76 2.2 130 3.34 2.2

10 0.72 1.9 070 1.99 2.2 140 3.56 2.2

20 0.90 2.0 080 2.22 2.2 150 3.79 2.2

25 1.0 --- 090 2.45 2.2 160 4.03 2.3

30 1.10 2.0 100 2.68 2.2 180 4.42 2.2

40 1.31 2.0 110 2.90 2.2 180 4.42 2.2

50 1.53 2.1 120 3.12 2.2 190 4.61 2.2

200 4.78 2.2

IM 12D7C2-01E-H

34

7-1. IntroductionThe EXA SC400 microprocessor conductivi-ty converter continuously monitors the con-dition of alll key components of the measu-ring system to ensure that measurement isdependable. If a fault is detected this is sig-nalled immediately. A maximum of 2 errorscan be shown in the display at the sametime by a code preceded by an E.The table on page 34 shows the errors innumerical sequence, giving a possible cuseand a suggested remedy.The remedy for each fault is given veryshort.Process conditions determine whataction can be taken to correct errors. As theactual situation may vary, it is not possiblefor us to give you a full solution for all cases.If you have any problem or question pleaseconsult your nearest YOKOGAWA sales orservice organisation for assistance.

Faults indicated with an asterisk (*) also trig-ger the FAIL-alarm contct and can thus bedetected from a distance.It is also possible to activate a special out-put signal (22mA and 1.1 V) in FAIL condi-tions.

7-2. Sensor selection

7-2-1. GeneralThe program of sales of YOKOGAWA inclu-des a wide range of conductivity cells withchemically resistant material like stainlesssteel, epoxy resin, PTFE of PVDF.Select a cell which adapts to your applica-tion.

7-2-2. Selection a conductivity cellFirst determine the range limits for the com-bination of conductivity cell and EXA SC400.The range of the EXA SC400 is from 2 µS x C to 500 mS x C (= 500.000 µS x C).

Note: At process values above 50 mS/cmselection of a 4-electrode conductivitycell is recommended.

Error code E6 indicates that a value ismeasured below 2 µS/cm x C and Errorcode E5 indicates that a value is measuredabove 500 mS x C .

7-2-3. Selecting a different cell constantThe EXA SC400 can be programmed toaccept any cell with a cell constant between0.01 and 50 cm-1 (see service code 03).

7-2-4. Integral temperature sensorThe EXA SC400 has been set at the factory(default) for a Pt1000 temperature sensor.Setting the instrument for an other tempera-ture elements is from the service code 01.

A seperate temperature sensor can be con-nected, if no integral temperature element ispresent in the conductivity cell.Select a Ni100, Pt100 or Pt1000 sensor forcorrect temperature compensation.

7. TROUBLE SHOOTING

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35

7-3. Diagnostics

7-3-1 GeneralThe EXA SC400 on-line sensor diagnosticswill indicate a fault due to the fouling orpolarisation of the connected sensors. Thefault will be indicated by teh activation of theFAIL-contact, the lighting of the LED and theflag in the display.

7-3-2 Diagnostics of the measuring loopDuring measurement the EXA SC400adjusts the measuring frequency to give thebest conditions for the actual value beingmeasured.At low conductivity there is a risk of errordue to the capacitive effects of the cableand cell. These are reduced by using a lowmeasuring frequency.At high conductivity the capacitive effectsbecome negligible and errors are more likelyto be caused by polarisation or fouling of thecell. These errors are decreased by incre-asing the measuring frequency.

7-3-3 Self-diagnostics of the cellAt all values the EXA SC400 checks the sig-nal from the cell to search for distortionwhich is typical of capacitive or polarisationerrors. If the cell becomes fouled this willtrigger the FAIL alarm.

It is possible to turn on and off sensor pola-risation check in service code 20 (default isoff).Using a 4-electrode cell will ingibit thepolarisation check

7-3-4. Self-diagnostics of the tempera-ture sensor

The temperature sensor, which is normallybuilt into the conductivity cell, is checked todetect damage of faulty connections.

NOTES:1. A temperature fault may be caused by

incorrect progrmming the type (see servi-ce code 01).

2. After detecting a temperture error (E7 ofE8), e.g. if the temperature is out ofrange, the temperature measurement isfixed at 25°C.

7-3-5. Self-diagnostics of the electronicsThe microprocessor’s operation is checkedby the watch-dog timer, initiating a reset ifthe normal function suffers severe interfe-rence. During reset the instrument checksthe integrity of the program and all storeddata. If a fault is detected the FAIL alarm isswitched on and the error is indicated onthe display.

7-4. Check during operationWhenever the EXA SC400 is being pro-grammed or calibrated, data are checkedand an error is shown when appropriate.Should this occur the newly programmeddata are rejected and the converter continu-es to work with the previous settings.

IM 12D7C2-01E-H

36

7-5. Error messages and explanation

Code Error description Possible cause Suggested remedyE1* Polarisation detected on cell Fouling of electrode surface Clean conductivity cell

Conductivity too high Select cell with higher constant

E2 Temperature coefficient out of limits Incorrect field calibration of temperature See adjustment (section 6.4)(exceeds -10 to +10 %/˚C range) coefficient Set calculated coefficient (service code 22)

E3 Calibration of limits Calibrated value differs more than 20% from Check for correct sensorprogrammed value in service code 02 Check the unit (µS/cm of mS/cm)

Repeat calibration (§5-1)

E5* Conductivity cell shortcircuited Incorrect wiring Check wiring (§3-2)Internal leakage of cell Replace cellDefective cable Replace cable

E6* Conductivity cell open Dry cell Immerse cellIncorrect wiring Check wiring (§3-2)Defective cable Replace cable

E7* Temperature high error (open sensor) Process temperature too high Correct settings (see service code 01)Wrong sensor programmed Check model code sensor Incorrect wiring Check connections and cable

E8* Temperature low error (sensor shortcircuited) Process temperature too low Correct settings (see service code 01).Wrong sensor programmed Check model code sensorIncorrect wiring Check connections and cable

E10 EEPROM write failed Fault in electronics Power on/off and re-enter dataIf not successful call your nearestYOKOGAWA office

E15 Temperature correction out of limits Temperature inaccuracy Check connections or program correctExceeds limits sensor type

E17 Output scan less that 60% Incorrect programming by user Repeat programming (§6-2)

E18 Incorrect entering of table Error during programming Repeat programming (see service code 06)

E19 Entered values not acceptable Incorrect programming by user Repeat programming

E20 All programmed values are lost Fault in electronics Call your nearest YOKOGAWA office

E22* Expire contact action interval Ineffective process control Check control loop

When errors appear which are not mentioned in this list, please consult the YOKOGAWA service organisation. A maximum of 2 errors can beindicated at the same time.

These errors will trigger the FAIL-output

IM 12D7C2-01E-H

37

8. SERVICE MODE

IntroductionThe EXA SC400 instrument is delivered tothe customer with a full set of operatingparameters. Most of these parameter set-tings enable you to start your conductivitymeasurement at once. These socalled def-ault parameters can be changed form thefollowing entries to optimise the instrumentfor your specific application. This fine tuninggives a superior performance over conven-tional analogue instruments.

The parameters can be put into fourgroupts:Group 1: Codes 01 to 03:

Cell characteristicsGroup 2: Codes 04 to 07:

Analogue output commissioningGroup 3: Codes 08 to 14:

Contact output commissioningGroup 4: Codes 15 to 55:

Auxiliary functions

If a function has to be adjusted, it is called-up with the cod mentioed. Having selectedthe code then gives you the possibility to eit-her activate or adjust the values for thisfunction. After this you will return to theentry point to make other adjstment or goback to the measuring status.

If errors are made during the programmingprocess, these will be indicated, no actionwill be taken and you can start the program-ming again.

IM 12D7C2-01E-H

38

Code Routine Use Chapter01 Temperature sensors and units Select sensor type and select units 8-102 Cell constant Adjust value 8-203 Measuring principle 2 or 4 electrode 8-304 Current output Select 0/4 - 20 mA 8-405 Activate output table Linear or non-linear 8-506 Build table Program values 8-607 Temperature output Select output mA/mV 8-708 Contact output S1 Program function 8-809 Contact output S2 Program function 8-810 Contact output S3 Program function 8-811 Alarm parameters Hysteresis and delay 8-912 Proportional control Set range 8-1013 Proportional control Set period 8-1014 Proportional control Set frequency 8-1-15 Reference temperature Adjust value 8-1116 Auto return Time out function 8-1217 Signal fail on output ”Burnout” function 8-1318 Temperature adjust Correct cable error 8-1419 Temperature compensation Adjust factor a 8-1520 Polarisation check Switch on or off 8-1621 % indication on second display Switch on or off and set values 8-1722 Expire Program timer on contact 8-1823 Temperature hysteresis Setting hysteresis temperature alarm 8-1924 Setpoint on maintenance level Activate possibility 8-2025 Matrix Select matrix temperature compensation 8-2126 Fail status Select hard/soft FAIL 8-2227 Enable/Disable E6 function E6 inactive/active 8-22a33 Passcode activation Protecting levels 8-2355 Restore defaults Erase values 8-24

IM 12D7C2-01E-H

39

8-0. Access to service settings

Remove cover by releasing 4 screws Display indicates *CODEEnter access code to select function

Display indicates current settingAdjust settings according to description in§8-1 to 8-24.

1. Access to service menu


YES NO MODE


YES NO MODE

ENT


YES NO MODE

ENT

Press this key for access to com-missioning mode*

Select service menuSelect digit to adjust

Adjust digit

Enter selected codeENTL

LSelect digit to adjust

Adjust value



ENT

L

L

MODE


Press NO-key until ‘SERV’ is indi-cated

NO

Confirm selection by pressingYES-key. The display will indicate‘CODE’

YES

SERV = Service menu

NOTE:If a password has been activated in §8-23 the display will indicate ‘PASS’ after pressing the YES-key. Enter the correct code to have access to the service mode.

2. Enter code to select required func-tion

3. Adjust setting (see individual routines)

IM 12D7C2-01E-H

40

8-1. Temperature sensor and unitAccess-code : 01 (see §8-0)Display : *T.CODE

Adjustments: (X.X)

8-2. Cell constantAccess-code : 02 (see §8-0)Display : 1.00 x C

Adjustments: 1. Select multiplying factor2. Adjust the required cell constantX.X

0.X Temp.- sensor = Pt1000 RTD1.X Temp.- sensor = Ni100 RTD2.X Temp.- sensor = NTC (Japanese

model)3.X Temp.- sensor = Pt100 RTDX.0 Temperature in ˚CX.1 Temperature in ˚C

Explanation:The program of sales of YOKOGAWA enclu-des a range of conductivity cells which havedifferent temperature sensors. The EXASC400 can be ajusted for different types.Check the Model code of the sensor for cor-rect adjustment.To adapt to the different markets a selectionbetween temperature units in °C and °F canbe made.

Default: 0.0 = Pt1000 and °C

Explanation:1. Multiplying factor1. - The multiplying factor is confirmed after

pressing the YES-key.1. - Change multiplying factor to 1.0 R 10 R

0.01 R 0.1 R 1.0 by pressing NO-keyand confirm selection with YES-key.

2. The value of the cell constant is indicatedin the specifications of the cell and/or onits identification plate.Adjust the required value of the cell.

A. Cell characteristics

X.XXX[Y] [N] 1. Select multiplying factor X.XXX 2. With keys > and /\ any cell con-

stant between 0.01 and 50.0cm-1 can be selected.

Select the required digit to adjust with key >(digit flashes).With key /\ the required value of the selec-ted digit can be set.

Default: 0.10 cm-1

Nominal limits: 0.008 to 50 cm-1

IM 12D7C2-01E-H

41

8-3. Measuring principleACCESS-CODE : 03 (see §8-0)DISPLAY : *4.ELEC

Adjustment: (X)Select the measuring principle of the trans-mitter.

8-4. Analogue current output signalACCESS-CODE : 04 (see §8-0)DISPLAY : *mA

Adjustment: X

X

0 2-electrode principle1 4-electrode principle

Explanation:Select the principle to cooperate with themeasuring sensor. The conductivity celldetermines which principle can be used.The 4-electrode principle is used for highconductivity values in general because itcompensates for polarisation and fouling.

Default: 0 = 2-electrode principle.

Explanation:The current output signal is determined bythe setting here.The mA output and the fixed voltage output(0-1 V) are linear function of conductivity (ifnot programmed otherwise through a tabel,see §8-5 and §8-6).One or both of the output signals can repre-sent temperature (see §8-7).The outputs are limited to a 2.5% overrange(20.5 mA and 1025 mV).The outputs can be programmed to give 22mA and 1100mV in a FAIL condition (see§8-13).The output signals can be frozen at a fixedor last occurring value with the HOLD func-tion (see §6-4).

Default: 1 = 4-20 mA

B. Analogue output commissioning

X0 0 to 20 mA1 4 to 20 mA

IM 12D7C2-01E-H

42

8-5. Linear/non-linear output selectionACCESS-CODE : 05 (see §8-0)DISPLAY : *TABLE

Adjustment: (X)

8-6. Table for a non-linear output rangeACCESS-CODE : 06 (see §8-0)DISPLAY : 0 - 100% in 21 steps

of 5%

Adjustment: In this routine a 21 step outputtable can be set (after activationin service code 05). Setting iswith keys > and /\.

X

0 Linear output range1 Non-linear output range (to be speci-

fied in service code 06)

Explanation:As standard both outputs are set for a linearoutput.A non-linear output can be selected for con-ductivity measurement only.Select 1 to activate the possibility to pro-gram a non-linear output. The actual pro-gramming of the output table is done in ser-vice code 06.

Default: 0 = Linear outputs

Explanation:The procedure will be explained using anexample:Sulphuric acid in the range of 0-25%and areference temperature of 25°C (see literaturefor conductivity curves at 25°C).

1. Define minimum value (0% sulphuric acid= 0 mS/cm).

2. Define maximum value (25% sulphuricacid = 791 mS/cm).

3. Divide range by 20 and calculate conducti-vity values (each point is 25/20 = 1,25%by weigth)

4. Fill in the table.

NOTE: Sometimes not all 21 values are known. If an unk-nown value is prompted, press NO-key. The con-verter will step to NEXT value and find the unk-nown point by interpolation.Alternatively you can set up a bilinear, logarithmicor hperbolic scale: examples to program thesescales are on the following page.

Output linear to concentrationExample: 0-25%-Sulfuric Acid

0 2 4 6 8 10 12 14 16 18 20 22 240

200

400

600

800

1000 100

80

60

40

20

0

Conductivity

% Output

Conductivity (mS/cm) Output in %

Condutivity

Output %

Concentration (% by wt)

Code mA Concentration Example Conductivity Example

% Output

0 4 0 0

5 4.8 1.25 60

10 5.6 2.5 113

15 6.4 3.75 180

20 7.2 5 211

30 8.8 7.5 335

35 9.6 8.75 383

40 10.4 10 424

45 11.2 11.25 466

50 12 12.5 515

55 12.8 13.75 555

60 13.6 15 590

65 14.4 16.25 625

70 15.2 17.5 655

75 16 18.75 685

80 16.8 20 718

85 17.6 21.25 735

90 18.4 22.5 755

95 19.2 23.75 775

100 20 25 791

IM 12D7C2-01E-H

43

% of conductivity range

% of output range

Percentage of mA-output range versus percentage ofconductivity range.

Example:A = bi-linearB = hyperbolic (2 decades)C = logarithmic (2 decades)D = linear

Output bi-lin log 2 log 3 hyp 2 hyp 30% 0.0 1.0 0.10 1.00 0.105% 1.0 1.3 0.14 1.20 0.2710% 2.0 1.6 0.20 1.82 0.4315% 3.0 2.0 0.28 1.90 0.6120% 4.0 2.5 0.40 2.00 0.8325% 5.0 3.2 0.56 3.75 1.1030% 6.0 4.0 0.79 4.80 1.3635% 7.0 5.0 1.12 5.92 1.6840% 8.0 6.3 1.58 7.00 2.0545% 9.0 7.9 2.24 8.31 2.4950% 10.0 10.0 3.16 10.00 3.0055% 20.0 12.6 4.47 11.85 3.6660% 30.0 15.8 6.31 14.00 4.3365% 40.0 20.0 8.91 16.65 5.2270% 50.0 25.1 12.6 19.50 6.8075% 60.0 31.6 17.8 23.80 8.2580% 70.0 39.8 25.1 29.55 11.085% 80.0 50.1 35.5 36.70 14.890% 90.0 63.1 50.1 48.50 21.895% 100.0 79.4 70.8 68.60 36.5100% 110.0 100.0 100.0 100.00 100.0

Exmple of output tables

bi-lin = bi-linear over 2 decadeslog 2 = logarithmic over 2 decadeslog 3 = logarithmic over 3 decadeshyp 2 = hyperbolic over 2 decadeshyp 3 = hyperbolic over 3 decades

Note: Multiply the values from the table with appropirate factorsto get the end-scale value you want.Special concentration tables can be programmed by theuser.

IM 12D7C2-01E-H

44

8-7. Temperature ouput signalACCESS-CODE : 07 (see §8-0)DISPLAY : *T. OUTP

Adjustment: (X)

8-8. Functioning of contacts S1, S2 and S3ACCESS-CODE : 08, 09, 10 (see §8-0)DISPLAY : *S1, *S2, *S3

Adjustments: X

X0 No temperature output; conductivity on

both mA and V.

1 Temperature on V output; conductivityon mA.

2 Temperature on mA output; conducti-vity on V.

Explanation:The actual process temperature can beswitched to one of the analogue output sig-nals. If the Volt signal is used, the conducti-vity will be on the mA output and vice versa.After selecting 1 or 2 you will be asked toenter a temperture range for the 0% or100% point. The minimum span is 50°C or°F. The temperature range is -10 to 200°C,15 to 395°F repectively.

Defaults: 0 = No temperature outputRange: 0-100°C of 32-212°F

Explanation:The settings determine the function of allthree output contacts S1, S2 and S3.If the first digit is either a 1 or 2 the contact isactivated and the setpoints can be adjustedin the SETPOINTS menu (see §6-1).The second digit chooses the functioning ofthe contact output. The process alarm func-tion is triggered by the changing processvalue. The hysteresis and delay-time are setin §8-9.The proportional duty cycle control uses thesetpoint and a proportional range (program-med in §8-10) to calculate the duty cycle ofthe contact output. The pulse period is fixed.The control range of the duty cycle isbetween 10 and 90%.

Outside the proportional range the dutycycle is 0% or 100%.The proportional pulse frequency controluses the setpoint and a proportional range(programmed in §8-10) to calculate thenumber of pulses. The maximum pulse fre-quency is fixed. The pulse duration time isfixed at 0.3 seconds.Further explanation in fig. 8-1, 8-2 and 8-3.

Defaults: S1: 2.0S2: 1.0S3: 0.0

X.X0.X Not activated1.X Low process alarm2.X High process alarm

X.0 Process alarmX.1 Proportional duty cycle controlX.2 Proportional pulse frequency controlX.3 Temperature alarm

Only after 1 or 2: Set temperature range

DISPLAY :*0% and 100%Adjustment: Temperature range for the out-

put signal

IM 12D7C2-01E-H

45

8-9. Settings for the process alarmfunction

ACCESS-CODE : 11 (see §8-0)DISPLAY : *D.TIME and *.HYST

Adjustment : Setting the delay time (inseconds) and hysteresis (in percent ofrange)

8-10. Settings for the proportional con-trol

ACCESS-CODE : 12, 13 and 14 (see§8-0)

DISPLAY : *RANGE, *PER,*FREQ

Adjustment: The proportional range(*RANGE) is set in percent (%) of the pro-grammed output range. The proportionalpulse period (*PER) is set in secondes.The proportional pulse frequency (*FREQ) isset in pulses per minute.Explanation:

The delay time is counted from the momentthe process value has passed the setpointof the alarm function. When dealing with ahigh (low) alarm the relay will switch backafter the process value has passed bothsetpoint minus (plus) the hysteresis. (see fig.8.1)The hysteresis (dead-band) is in percent ofthe programmed range.The programmed values are shared by allthree contacts. (S1, S2 and S3).

Note: For hysteresis on temperature contactfunction, refer to service code 23 (§8-19).

Default: Delay time 0.2 s limits 0.0-200 sHysteresis 2.0% limits 0.1-100%

Explanation:It is only useful to select these values whenone or more contacts will be used for pro-portional control. The selection of the pro-portional control action is from §8-8.Whether you have selected proportionalduty cycle control or proportional pulse fre-quency control, you have to program theproportional range with access code 12 forboth. This determines the range in which thecontrol takes place and changes the controloutput between 0% and 100%.

The proportional pulse period needs to beset when duty cycle control is selected. Thepulse period can be set between 5 to 100seconds. The duty cycle is controlledbetween 10% and 90% by the deviationfrom the setpoint with the proportionalrange (see fig. 8-2).

The proportional pulse frequency needs tobe set when pulse frequency control is pro-grammed. The maximum number of pulsescan be set between 50 to 120 pulses perminute. The number of pulses is controlledbetween zero (0) and the programmedmaximum by the deviation from the setpointwithin the proportional range (see fig. 8-3).

Note: Proportional control only for contactoutput allocated to conductivity.

Defaults: Proportional range 10% limits 0-100%Proportional period 10 seconds limits 5-100 sProportional frequency 70 per minute limits5-120/minute

IM 12D7C2-01E-H

46

SC

LED Off LED On LED Off

100

50

0

ont toff

50%

90%

10%90%

50%

10%

100

50

0

SC

0.3 s

Fig. 8-1. Delay time and hysteresis

setpoint

Setpoint

t on t off

timeProportionalrange

SetpointNo Pulses

Maximum Pulse Frequency

Proportionalrange

Pulse Period

Hysteresis

t (sec)delay time

% Controller % Controller output

delay time

Fig. 8-2. Duty cycle control Fig. 8-3. Pulse frequency control

time

IM 12D7C2-01E-H

47

8-11. Reference temperatureACCESS-CODE : 15 (see §8-0)DISPLAY : *T.R.˚C or *T.R.˚F

Adjustment: Setting the reference tempera-ture used in the calculations. Normally thisvalue will be 25°C or 77°F.

8-12. Auto returnACCESS-CODE : 16 (see §8-0)DISPLAY : *RET

Adjustment: (X)

Explanation:For easy referencing all measured values arecompensated for temperature to 25°C. Thistemperature is easily produced at laboratoryconditions and most literature data use thistemperature. In exceptional cases it is pos-sible to use a different reference temperatu-re in combination with a programmed tem-perature compensation factor (e.g. concen-trated sulphuric acid measurement).

Default: T.R. = 25°C; Limits: 0-100°C/30-225°F

Explanation:As a safegaurd against long maintenancejobs or unintentionally pushing a button it ispossible to let the system return to its nor-mal function of measurement when no keysare pushed for 20 minutes.If the HOLD function is activated the auto-matic return function will take the instrumentto HOLD after 10 minutes and switch tomeasurement after another 10 minutes if nokeys are pressed.

Default: Automatic return activated

X0 No automatic return to measurement

1 Automatic return to measurement after20 minutes

48

IM 12D7C2-01E-H

8-13. Signalling of fail condition

ACCESS-CODE : 17 (see §8-0)DISPLAY : *BURN

Adjustment: (X)

8-14. Temperature sensor and cablelength adjustment

ACCESS-CODE : 18 (see §8-0)DISPLAY : *.ADJ and *L.ADJ

Adjustment:

Explanation:Besides the indication in the display and theswitching on the FAIL contact, a special outputsignal can be activated to indicate a fault in themeasuring loop. The signal is non both outputs(mA and V) and has a value outside the normalanalogue span. For the V-output a signal of1.100 V is sent.It is necessary to check the connected equip-ment (e.g. strip-chart recorder, control system)for a possibility to react to this signal level. If analarm can be set to react on this signal level anextra safety against irrelevant measurementcan be built into the system.The signal uses the same convention as isused in thermocouple ‘burn-out’ detection bygoing up-scale. The upper limit of the normalsignal is 20.5 mA and 1.025 V.

Default: 0 = Not activated.

Explanation:The temperature measurement uses a resi-stance measurement. In this kind of meas-urement the length of the connecting cablecan influence the accuracy of the tempera-ture indication. To compensate for the extraresistance of the cable up to 5q can beadjusted.Connect the correct temperature sensor tothe EXA instrument and insert it in a stabletemperature bath of a known value.Check the temperature indicated at this set-ting in ˚C or ˚F and adjust the value to thecorrect temperature of the bath.Now the EXA transmitter has been calibra-ted to compensate for the extra cable resi-stance.It is advised to use a Pt1000 sensor for bet-ter accuracy on the measured temperatureand the resulting temperature compensa-tion.

X0 Adjust the value of the indicated tem-

perature (˚C/˚F) to that of the actualtemperature.

1 Adjust the length of the cable used inthe measurement.

X0 No special output signals on FAIL

1 Special output signals on FAIL activa-ted

Next the cable length can be adjusted(*.L.ADJ). When using a conductivity cableother than type WU40-LH2 (length 2meters), the cable capacity will influence theaccuracy of the measurement in the purewater region. Adjust for the cable by adjus-ting the displayed length. No values under 2meters are accepted. The maximum value is10 meters. The compensation is based onthe characteristics of Yokogawa’s conducti-vity cable (type WU40-LH5 and WU40-LH10).

Default: No compensation

IM 12D7C2-01E-H

49

8-15. Temperature compensation coef-ficient adjustment

ACCESS-CODE : 19 (see §8-0)DISPLAY : *T.C.

Adjustment: Adjust the value of the manu-ally set compensation factor

Explanation:In addition to the procedure described in§4-5 it is possible to adjust the compensa-tion factor directly. If the compensation fac-tor of the sample liquid is known from labo-ratory experiments or has been previouslydetermined, it can be introduced here.Adjust th value between -10.00 o +10.00 %per °C. In combination with the referencetemperature setting at §8-11 a linear com-pensation function is obtained, suitable forall kinds of chemical solutions.

Default:skipped, compensation for NaCl isautomatic

NOTE: Access to this routine is only possi-ble when manually set temperaturecompensation factor (Ω) is selectedin §6-4.

Sulphuric Acid

Temperature coefficient

Conductivity (mS/cm)

Temperature (°C)

Kt - Kref x 100α = X

T - Tref x Kref

3%

50

IM 12D7C2-01E-H

8-16. Polarisation check

ACCESS-CODE : 20 (see §8-0)DISPLAY : *POL.CK

Adjustment: (X)

8-17. Percent by weight indication onsecond display line

ACCESS-CODE : 21 (see §8-0)DISPLAY : *%

Adjustment:

Explanation:The EXA SC400 normally checks the signalfrom the cell to search for distortion of capa-citive or polarisation errors. If there is a pro-blem with the installation or the cell beco-mes fouled this will trigger the E1 fault sign-al.In some installations this error detecting cancause unwanted signals during operation.Then the possibility to disable this check willbe used.

Note: When 4-electrode measurement ischosen this checking is not perfor-med.

Default: OFF

Explanation:If a conductivity measurement is used forconcentration monitoring, it can be conve-nient to link the measured conductivity valueto a % by weight concentration value. Alinear concentration indication in % units isprogrammed by entering two values.- X in 3 digits corresponds to 0% of the

output value (= 4 mA)- Y in 3 digits corresponds to 100% of the

output value (= 20 mA)

X0 OFF1 ON

X0 OFF1 ON

Example:0% output si 93.0% by weigth100% output is 99.0% by weigth

The instrument uses interpolation betweenthe entered values. As the relation betweenpercent by weight concentration and con-ductivity is not linear in most cases, the pos-sibility to linearize the output to concentra-tion units can be used. Refer to §8-3 and§8-4. The instrument becomes a concentra-tion meter by output function and (second)display (line) based on a conductivity meas-urement.

Default: OFF

Generation of the fault E1 can be switchedon or off.

Select the possibility to display % by weighton the second display line. When % indica-tion is activated (Select 1) the display rangecan be adjusted:* 0%: Adjust low span display value* 100%: Adjust high span display value

IM 12D7C2-01E-H

51

8-18. Timer on contact function

ACCESS-CODe : 22 (see §8-0)DISPLAY : *EXPIR/*tE.min

Adjustment: (X)

8-19. Settings for the temperature hys-teresis

ACCESS-CODe : 23 (see §8-0)DISPLAY : *T.HYST

Adjustment: Setting the hysteresis for set-point of contact allocated toprocess temperature

8-20. Setpoint setting on maintenancelevel

ACCESS-CODE : 24 (see §8-0)DISPLAY : *MODE

Adjustment: (X)

Explanation:When the contacts are used for a controlfunction the contact action should resulteffect.If this effect (=measurement within safeband) is not reached withing the set expiretime an error E22 is triggered (see also §8-17).The E22 can be eliminated by pushing the[YES] or [NO] keys. The timer is reset.

Default: 0 = no timer

Explanation:When dealing with a high (low) alarm therelay will switch back after the process valuehas passed both setpoint minus (plus) hys-teresis. The hysteresis (dead-band) can beadjusted in absolute for temperature meas-urement.A specific setting of the hysteresis is valid forall contacts allocated to that specific para-meter.

Default:

X0 Setpoints programmable on commis-

sioning level only (*key)1 Setpoints also programmable on main-

tenance level (MODE key)

X0 No timer1 Timer function activated

When 1 is selected use [>] and [^] keys toprogram the contact action expire time inminutes.

Default Limits Units

2.0 0.0-199.9% % of SCrange

0.5 0.1-5.0 ˚C

0.9 0.2-10.0 ˚F

Explanation:Normally setpoints of the contact outputscan only be adjusted on commissioninglevel. To get access, the cover has to beremoved. For convenience the setpointsadjustment routine can be made availableon maintenance level; access through coverwindow.

Default: 0 = setpoint setting not available onmaintenance level.

52

IM 12D7C2-01E-H

8-21. Selection of standard electrolytesACCESS-CODE : 25 (see §8-0)DISPLAY : *MATRX

Adjustment: (X)

ExplanationThe SC400 is equiped with a matrix typealgorithm for accurate temperature compen-sation. In this routine the required selectioncan be made.

NOTE : Access to this code is only possible if tem-perature compensation in section 6-4 is setto T.C.

HCL-P °C 0 pbb 4 pbb 10 pbb 20 pbb 100 pbb10 0.023 0.0352 0.0631 0.116 0.565 in uS/cm20 0.0419 0.055 0.0844 0.145 0.67730 0.071 0.085 0.115 0.179 0.78740 0.113 0.129 0.159 0.225 0.897 50 0.173 0.190 0.220 0.286 1.008

AMMON °C 0 pbb 2 pbb 5 pbb 10 pbb 50 pbb10 0.023 0.0337 0.0651 0.122 0.535 in uS/cm20 0.0419 0.0512 0.0842 0.15 0.64830 0.071 0.0788 0.111 0.181 0.75840 0.113 0.120 0.149 0.221 0.86650 0.173 0.178 0.203 0.273 0.974

MORPH °C 0 pbb 20 pbb 50 pbb 100 pbb 500 pbb10 0.023 0.0402 0.0807 0.139 0.431 in uS/cm20 0.0419 0.0584 0.108 0.185 0.59230 0.071 0.0851 0.140 0.235 0.76340 0.113 0.124 0.181 0.289 0.93850 0.173 0.181 0.234 0.351 1.12

HCL-C °C 1% 2% 3% 4% 5%0 65 125 179 229 273 in mS/cm15 91 173 248 317 379 30 114 217 313 401 477 45 135 260 370 474 565 60 159 301 430 549 666

HNO3 °C 1% 2% 3% 4% 5%0 39.5 76.1 113.4 147.2 179.5 in mS/cm20 57.4 108.5 161.4 210.0 258.0 40 81.4 148.1 215.0 275.0 330.0 60 99.9 180.8 260.0 331.0 397.0 80 127.8 217.0 299.0 374.0 448.0

The actual matrices are :

X0 Access code 101 Cation conductivity,

traces HCl in water HCL-P 10-50°C2 Boiler feed water, traces

ammonia in water AMMON 10-50°C3 Morpholine in pure

water MORPH 10-50°C4 Hydrochloric acid

HCl (0-5%) HCL-C 0-60°C5 Nitric acid HNO3

(0-5%) HNO3 0-80°C

IM 12D7C2-01E-H

8-22. Fail status signallingACCESS-CODE : 26 (see §8-0)DISPLAY : *Err.X

Adjustment: (X)

Explanation:As described in chapter 7, the error codemarked with an asterisk (*) in section 7-5normally will trigger a number of actions: theFAIL contact closes; the FAIL flag and LEDare lit; all other contacts (S1, S2, S3) aredeactivated and (when activated in 8) theoutput signals go up to 22 mA.

In this service routine for each (asterisk mar-ked) error code and cell the actions can bereduced to a flashing FAIL flag and LED anda pulsating FAIL contact.

Default: All codes = 1 (fully signalling)

X

0 Error triggers flashing FAIL flag andLED and pulsating FAIL contact

1 Erro triggers continuous FAIL flag andLED, continuous FAIL contact and, ifactivated, a 22 mA output signal. Allother contacts will be deactivated.

8-22a. Enable/Disable E6 functionACCESS CODE : 27 (see §8-0)DISPLAY : EN.E6

Adjustments : X

Explanation :This entry makes it possible to enable/disa-ble the E6 function, which may be necessarywhen measuring at low conductivity or highresistivity.Default: 1 (E6 active)

X0 E6 inactive1 E6 active

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IM 12D7C2-01E-H

8-24. Restore default settings

ACCESS-CODE : 55 (See §8-0)DISPLAY : *ERASE

Adjustments : YES = Replace all user programmed data

by defaults.NO = Keep user programmed data as

before.

Explanation:This entry is provided to give you the possi-bility to ERASE all previously programmedvalues and replace them with the factory setdefault values. If you press YES the data inthe non-volatile memory will be replaced bythe default values.Please keep in mind that there is no possibi-lity to retrieve data after you pressed YES!This also gives you the opportunity to usethe instrument in another set-up and startwith the default values again.

WARNING:Do not use this code without properauthority as all settings, programmedfunctions and tables will be lost!

8-23. Passcode protection by three digitcode

ACCESS-CODe : 33 (see §8-0)DISPLAY : *PASS

Adjustments: (X.X.X)

0 = No passcode1 = Passcode is 1112 = Passcode is 3333 = Passcode is 7774 = Passcode is 8885 = Passcode is 1236 = Passcode is 9577 = Passcode is 3318 = Passcode is 5469 = Passcode is 847

X.X.X0.X.X Protection on Maintenance level

inactiveX.0.X Protection on Commissioning level

inactiveX.X.0 Protection on Service level inactive

#.X.X Protection on Maintenance levelactivated

X.#.X Protection on Commissioning levelactivated

X.X.# Protection on Service level activa-ted

Note: # can be a digit from 1 to 9, and it willgive a protection according to theschematic below of the programmedlevel.

Explanation:In some cases a protection of operationlevels is wanted. In this way unauthorizedaccess to any of the 3 levels can be blockedby a simple passcode. When a passcode isselected for an operation level, access tot-hat level can only be obtained after enteringthe passcode. The display will show a mes-sage *PASS* to indicate the entry of thepasscode is required.

Note: For the Maintenance andCommisssioning level the passcodeentry is always requested when ente-ring from the measure mode.

- For the Service level the passcode entry isrequested after pushing the YES-key(see§8-0).

- When the Service level protection is activa-ted, the passcode cannot be changed byunauthorized persons.

Default: 0.0.0 (no passcode protection).

9-1. Conversion from conductivity toresistivity measurement

The EXA SC400 converter isa manufacturedas a conductivity measuring instrument. Forusers who want to measure resistivity it ispossible to convert the function of the ins-trument to a rsistivity measuring instrument.The procedure for this conversion is as fol-lows:1. Swirch off the power supply.2. Remove the cover of the EXA SC400 by

loosening the 4 captive screws (refer tofig. 3a, page 8).

3. Swing the display board to the left like adoor.

4. Switrch the blue jumper, located on theuppetion 1 to position 2:

9-2. Resistivity operationThe operation od a resistivity measuring EXASC400 converter is in all functions similar tothe conductivity measuring instrument.

9-3. Resistivity default valuesThe resistivity default values are similar tothe conductivity default values with threeexceptions:

9. RESISITIVITY MEASUREMENT

from position for conductivitymeasurement

to position for resistivity measurement

5. Swing back the display board and switchon the power supply.

6. Download the resistivity default valueswith the routine under access-code 55 inthe Service Mode (refer to §8-24).

7. Commission the instrument to your needsor use the resistivity default settings (referto §8-3).

8. Close the instrument by refitting thecover.

- Setpoint No. 1 1,0 kΩ cm- Setpoint No. 2 100,0 kΩ cm- Range 2Ω cm - 20 MΩ

9-4 Resistivity temperature compensa-tion coefficient

The temperature compensation coefficient“α” used for resistivity measurement is derived from the formula described in §6-4 item 2.In resistivity units the formula is convertedinto:

Rref - Rt x 100α = X [%/˚C]

T - Tref x Rref

Default values

IM 12D7C2-01E-H

55

9-5 Resistivity calibration solutionsThe table below shows typical resistivityvalues for solutions which may be made upin the laboratory.

% weight mg/kg Resistivity

00,001 10 ,046,700 kΩcm00,003 30 ,015,600 kΩcm00,005 50 ,009,430 kΩcm00,01 100 ,004,760 kΩcm00,03 300 ,001,621 kΩcm00,05 500 ,971,000 kΩcm00,1 1000 ,503,000 kΩcm00,3 3000 ,176,000 kΩcm00,5 5000 ,106,000 kΩcm01 10000 ,056,000 kΩcm03 30000 ,020,000 kΩcm05 50000 ,012,000 kΩcm10 100000 ,007,000 kΩcm

Table for NaCl at 25°C

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IM 12D7C2-01D-H

APPENDIXSOFTWARE VERSION 2.0 COMPAREDWITH 1*In 1994 the software of EXA SC400 hasundergone a major software update as aresult of customer feedback. The basicfunctioning of the EXA SC400 remainsunchanged, but the flexibility of the unit isenhanced by these changes. In order toenable the user to utilise these upgradesfully, we like to summarise these changesbelow.

1. Change alarm setpoints from frontpanel

In some applications the setpoints have tobe changed frequently. Normally the set-points are set in “Commissioning level”.Then the cover has to be removed to getaccess to this key. In Service code 24 theuser can promote *SETP from“Commissioning level” to “Maintenancelevel”.

2. Time-out function on alarmIf an alarm contact is used for control pur-poses, an alarm that stays ON too long mayindicate a system problem. In Service coide22 a maximum alarm “ON” time can be pro-grammed. After expiration of this time anerror 22 is displayed.

3. Allocation of alarm contact to tempe-rature

In Service codes 08, 09 and 10 it is possibleto use the contact outputs for Temperature.The hysteresis can be set in code 23. This isespecially useful for applications wheresample cooling is required.

4. Selection of ‘Soft’ or ‘Hard’ FAIL sign-alling

When an error message is defined as SOFTalarm in Service code 26, the FAIL contactand the FAIL flag are flashing, and the alarmcontact function is still active. If the error isdefined as HARD contact, the ALARM func-tion is cancelled in case of FAIL.

5. Matrix temperature compensationIn addition to the standard NaCl type tem-perature compensation and the use of alinear temperature compensation coefficientthe SC400 has a MATRIX type temperaturecompensation.This MATRIX type temperature compensa-tion offers increased accuracy in acidic andneutral pure waters.

IM 12D7C2-01E-H

57

SPARE PARTS

Description Partno. Pos. No.

Cover assembly, incl. 4 pcs. M4x20 screws K1541JG 1, 2, 3Digital and display board assembly K1541AF 4, 5EPROM with software K1541BE 6Protective cover assembly for power terminals K1541JH 7, 8Input and power board assembly incl. flat cable K1541AL 9, 10, 13, 14, 15110/220 V AC versionInput and power board assembly incl. flat cable K1541EL 9, 10, 13, 14, 1524 V AC versionInput and power board assembly incl. flat cable K1541DL 9, 10, 13, 14, 1524 V DC versionFuse holder L1823AA 9Fuse (box of 10 pcs.) for 220 V AC, 0,063 A K1543AD 10Fuse (box of 10 pcs.) for 110 V AC, 0,1 A K1543AE 10Fuse (box of 10 pcs.) for 24 V AC, 0,5 A 12.502.11 10Fuse (box of 10 pcs.) for 24 V DC, 1,0 A K1543AF 10Protective screen assembly for power board assembly K1541JQ 11, 12Housing assembly K1541JS 16, 17Gland set 1/2 “-NPT K1500AU 18

58

IM 12D7C2-01E-H

EXPLODED VIEW

IM 12D7C2-01E-HSubject to change without notice Printed in The Netherlands, 04-708 (A) QCopyright©

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