YOKOGAWA SC200 User manual

Instruction
Manual
Model SC200
2-wire Conductivity
or Resistivity transmitter
IM 12D7B2-E-H
4th edition

IM 12D7B2-E-H
FAILHOLD
MEASURE
CAL
DISPLAY
HOLD
YES NO
ENT
OUTPUT
SET HOLD
TEMP.
SERVICE
*
NO MODEYES
>
ENT>
MODE
mS/cm
MΩ/cm
kΩ/cm
µS/cm
.
ADJUSTMENT KEYS
: Choose digit
for adjustment
: Adjust digit (to decrease
pass through zero)
ENT: Enter new value
MEASURE VALUE
DISPLAY
MESSAGE
DISPLAY
KEY PROMPT
FLAGS
SELECTION KEYS
YES: Accept
setting
NO: change to
new setting
L
L
SELECT MODE
MEASURE/MAINTENANCE
Can be used
to escape
program at any time
SELECT MODE
MEASURE/COMMISSIONING
OUTPUT
HOLD FLAG MANUALLY SET TEMPERATURE
COMPENSATION
FLAG
FAIL
FLAG MENU POINTER FLAGS
MENU FOR
MAINTENANCE
FUNCTIONS
see chapter 5
MENU FOR
COMMISSIONING
FUNCTIONS
see chapter 4
Note: First digit changes from 1,-1,- to blank.
TEMP.MAN

IM 12D7B2-E-H
1. INTRODUCTION
1-1. Application.................................................................1
1-2. Required components for
conductivity measurement .........................................1
1-3. Identification...............................................................2
2. TECHNICAL SPECIFICATIONS .........................................2
2-1. General technical specification ...................................2
2-2. Functional description ................................................3
3. INSTALLATION AND WIRING............................................4
3-1. Installation and dimensions ........................................4
3-1-1. Installation site.................................................4
3-1-2. Mounting methods ..........................................4
3-2. Wiring of sensors .......................................................6
3-2-1. General precautions ........................................6
3-2-2. Additional precautions for installations in
hazardous areas..............................................6
3-2-3. Grounding the liquid ........................................6
3-2-4. Access to terminal and cable entry..................6
3-2-5. Connecting diagram for sensors......................7
3-3. Wiring of power supply...............................................8
3-3-1. General precautions ........................................8
3-3-2. Additional precautions for installation
in hazardous areas ..........................................8
3-3-3. Access to terminal and cable entry..................8
3-3-4. Power on ........................................................8
4. COMMISSIONING.............................................................11
4-1. Operations overview ................................................11
4-2. Output range adjustment ............OUTPUT ..............12
4-3. Set up Hold function ...................SET HOLD ...........14
4-4. Temperature compensation ........TEMPERATURE ...16
4-5. Sensor selection and diagnostics` ............................18
5. MAINTENANCE.................................................................20
5-1. Calibration...................................CAL......................20
5-2. Selecting a value to display .........DISPLAY ..............22
5-3. Use of the hold function ..............HOLD...................24
6. TROUBLE SHOOTING......................................................26
6-1. Introduction .............................................................26
6-6. Error messages and explanation ..............................27
7. SERVICE (Mode) ...............................................................28
7-1. Introduction .............................................................28
7-2. Access to service settings........................................29
7-3. Temperature sensors and units................................30
7-4. Reference temperature ............................................30
7-5. Output code selection..............................................30
7-6. Output table for non-linear range .............................31
7-7. Cell constant adjustment..........................................31
7-8. Auto return function .................................................31
7-9. Measuring principle..................................................32
7-10. Temperature sensor adjustment...............................32
7-11. Signalling of fail condition.........................................32
7-12. Temperature compensation coefficient adjustment ..33
7-13. Percent by weight indication on second
display line ...............................................................34
7-14. Polarisation check....................................................34
7-15. Passcode protection by three digit code..................35
7-16. Restore default setting .............................................35
7-17. Non linear ranges.....................................................36
CONTENTS

IM 12D7B2-E-H
8. CLASSIFICATION .............................................................36
8-1. Cenelec ...................................................................36
8-2. FM...........................................................................37
9. CHANGE FROM CONDUCTIVITY TO
RESISTIVITY MEASUREMENT ............. ............................38
9-1. How to change from conductivity to resistivity
measurement...........................................................38
9-2. Resistivity measurement ..........................................38
9-3. Maintenance of the transmitter.................................38
10. SOFTWARE VERSION 3.0
COMPARED TO VERSIONS 1 AND 2 ............................39
10-1. Cell constant............................................................39
10-2. Matrix compensation ...............................................39
10-3. Matrix temperature-compensation range .................40
10-4. Matrix data...............................................................40
10-5. Selection between “soft” or “hard” Fail situations .....41
10-6. Selection between yes or no E6 Fail-message .........41
10-7. Matrix examples.......................................................42

IM 12D7B2-E-H
1
1. INTRODUCTION
1-1. Application
The EXA SC200 transmitter is a 2-wire con-
ductivity instrument intended to be used in
industrial installations in the field. For easy
maintenance and operation it should be
located close to the sensors.
The cable length is limited to 10 metre.
It is powered from a remote low voltage DC
power supply through the 2-wire connec-
tion.
The EXA SC200 is compatible with most
commercial available conductivity sensors
and fitting systems.
The instrument is available in two versions:
- A general purpose version for use in safe
areas.
- An intrinsically safe version for use in
hazardous areas. The instrument can then
be installed in Zone 1 with the sensors in
Zone 0 or Zone 1.
The micro-processor is used in this instru-
ment for continuous loop diagnostics, flexi-
ble on site commissioning and fine tuning by
advanced functions.
In general a conductivity loop can be set up
for different purposes:
- To be part of a total process control sys-
tem.
- To indicate dangerous limits of a process.
- To monitor product quality.
1-2. Required components for
conductivity measurement
A. a conductivity sensor ( also called con-
ductivity cell) with integral temperature
sensor Ni-100 or Pt-1000.
B. a fitting for the above sensor with acces-
sories.
C. a signal cable with or without extension
boxes etc.
D. the EXA SC200 2-wire transmitter with
universal mounting accessory for wall,
pipe or panel mounting.
E. a DC power supply (nominal 24 V DC)
with cabling and optional zener barriers or
an intrinsic safe power supply.
F. peripherals: e.g. strip-chart recorder,
panel indicator, PID-controller
1-3. Identification
The instrument has an identification label,
which is fixed to the front plate.
This serves as a reference for the full model
code, power supply voltage and serial num-
ber. This label also carries authorised marks
to certify compliance with the current regu-
latory norms.
MODEL
SERIAL NO.
SUPPLY

IM 12D7B2-E-H
2. SPECIFICATIONS
2-1. General specifications
A. Intrinsic safety (model SC200S only)
- BASEEFA : Certified by and meets the requirements
of EEx [ia] ib IIC T4 of CENELEC
Certificate No.: 89C2379.
- FM : For IS CL1, DIV1, GP ABCD
T3B for TA-30 to 70˚C
T4 for TA-30 to 40˚C
Approval report: J.I. 1Y1A7.AX
- CSA : For Ex[ia] Class 1, Div. 1, Groups C
and D, T4A
Approval file: LR 102851-1
B. Indicating range : 0.055µS/cm to 2000 mS/cm at 25˚C
reference temperature with cell-con-
stants between 0.01 to 10 cm-1
C. Transmission signal : 4 - 20 mA DC; maximum load.550 Ω.
D. Transmission range : User programmable to any range within
the indicating range with a maximum of
60% zero suppression.
A user programmable output table can
be set up in 21 steps.
E. Power supply
- Model SC200G : 17 to 40 V DC, dependent on load.
- Model SC200S :
17 to 31,5 V DC, powered from a certified
zener barrier or isolated power supply
F. Climatic condition
- Ambient temperature : -10 to +55 ˚C(10 to 130°F)
- Storage temperature : -30 to +70 ˚C (-20 to 160°F)
- Relative humidity : 10 to 90%
- Weather protection : Rain and dust-tight to IP65 (NEMA 4X)
- Interference protection : EMI Class B
RFI less than 2% at 5 V/m for
20 MHz to 1 GHz.
G. Display method : Custom liquid crystal display.
- Main display : 31/2digit, 12.5 mm high.
- Message display : 6 alphanumeric characters, 7 mm.
- Special fields : Flags for status indication.
: Units: µS/cm, mS/cm.
: Key prompts: YES, NO, ^, >, ENT
H. Keys : 6 keys operated through the flexible win-
dow with tactile feedback and one hid-
den key behind the front cover.
I. Housing
- Body material : Cast aluminium with chemical resistant
coating.
- Window : Flexible poly carbonat.
- Colours used : Moss green/ off-white.
- Cable glands : Polyamide
- Cable entries : Two glands PG 16 (1/2” NPT adapter for
US Model).
Hose connection optional.
- Terminals : For maximum 2.5mm2cable (cable
finishings preferred).
- Earth connection : For external ground.
J. Mounting possibilities
- Bracket mounting : Two M6 bolts, 9 mm length.
Wall, or pipe mounting by the optional
mounting kit, panel mounting by self tap-
ping screws.
K. Shipping details
- Dimensions : 162 x 178 x 115 mm
(6.5 x 7 x 4.5”)
- Package : 290 x 225 x 170 mm
(11.5 x 8.9 x 6.7”)
- Weight : approx. 2,5 kg (5 Ibs)
L. Safety and security
- Data protection : Non volatile memory(EEPROM).
- Data backup : All data is stored 3 times.
- Interference test : according to IEC 801.
- Power down : no effect, reset to measurement.
- Operation : All 3 levels can be protected with a 3
digit passcode.
2

IM 12D7B2-E-H
3
2-2. Functional description
The EXA SC200 is a real time micro-control-
ler operated conductivity-analyzing system.
It uses a dedicated micro-controller to con-
trol all function necessary in such a system.
The input and output functions are concen-
trated in the analogue section of the instru-
ment. Even these functions are operated
through special interfaces designed to give
a minimum of interference problems to the
digital functions. A separation of function is
strictly executed.
By using very low power components it is
possible to make a complete micro-compu-
ter system work on less than 4 mA current.
By using an EEPROM for essential informa-
tion the operating parameters are fixed in
memory without the need for batteries. The
supply-voltage is stabilized by regulators to
the internal supply system. Any voltage
between 17 and 40 Volt is acceptable.
The user-interface is limited to a basic set of
6 keys accessible through the flexible win-
dow cover.
The software is designed with the user in
mind. It uses a simple 3 layer set-up to
communicate with the operator by giving
messages on the second line of the display
area and indicating which keys are to be
pressed in the display too.
The keys are scanned continuously and the
actions are taken immediately. An extensive
system of checking values and parameters
is implemented.
The EXA SC200 operates just like a normal
2-wire instrument but with additional func-
tions. These extra functions are possible by
using a micro-controller at the heart of the
system.
- Continuous sensor polarisation checking
during measurement.
- Automatic optimisation of measuring pulse
frequency and reference voltage.
- Accurate temperature compensation by
non liner NaCI algorithm.
- Simple output range adaptation making it
a versatile instrument.
- A HOLD-function for the current output
signal.
- Selection of temperature sensors.
- Passcode protection.
Additionally YOKOGAWA designed the in-
strument in such a way that an intrinsically
safe version is available with the same featu-
res and specifications. In fact the instrument
is only adapted slightly to fulfil the require-
ments of CENELEC.
The instrument comes in 2 versions only:
-A general purpose model.
-An intrinsically safe model.
This makes it easy to set up the instrument
on site and valuable for large scale exchan-
ges or emergency operations.

IM 12D7B2-E-H
3. INSTALLATION AND WIRING
3-1. Installation and dimensions
3-1-1. Installation site
As the transmitter is a rain-tight type, it can
be installed outdoors as well as indoors. It
should, however, be installed as close as
possible to the sensors avoiding long cable
lengths between sensors and transmitter.
The certified version can be installed in Zone
1.
Select an installation site where:
- mechanical vibrations and shocks are neg-
ligible;
- no relay/power switches are in the direct
environment;
- the transmitter is not mounted in direct
sunlight and severe weather conditions;
- maintenance activities are possible (no
corrosive atmospheres).
The ambient temperature and humidity
should be the limits of the specifications.
3-1-2. Mounting methods
The EXA SC200 transmitter has universal
mounting possibilities:
- panel mounting using selftapping screws;
- surface mounting on a plate (by bolts from
the back);
- wall mounting on a bracket (e.g. thick brick
wall);
- pipe mounting using a bracket on a hori-
zontal or vertical pipe (maximum diameter
50 mm);
Panel-mounting Surface mounting
Cut-out dimensions for panelmounting Dimensions
4
2 x M6 (bolts)
Unit: mm (inch)
162 (6.4)
115 (4.5)
77
180 (7)
30 (1.2)
Unit: mm (inch)
min. 203 (8)
min. 229 (9)
172 (6.77)
154(6.06)
30 (1.18)
2x ø4

IM 12D7B2-E-H
5
Universal pipe/wall mounting
Wall mounting Pipe mounting
(vertical)
Pipe mounting
(horizontal)
2" I.D. pipe
2" I.D. pipe
115
200
70
4x ø10
2x ø6.6
56
77

IM 12D7B2-E-H
3-2-4. Access to terminal and cable
entry
1. To access terminals remove the front
cover of the EXA SC200 by releasing the
4 captive screws.
2. Pull the sensor cable into connection
space and connected the wires to the
terminals as indicated by the numbers on
the wires. Make sure all connections are
firm and do not touch each other.
3. Screw the gland securely and tighten it to
keep out moisture. DO NOT use a
wrench to tighten the nut.
4. A hose connection can be used to guide
the cables coming from an immersion fit-
ting through a protective plastic tubing to
the transmitter. This adaptor has to be
bought separately.
3-2. Wiring of sensors
3-2-1. General precautions
Generally, transmission of signals from the
conductivity sensor is at a low voltage and
high impedance level. Thus care must be
taken to avoid interference.
Before connecting the sensor cable to the
transmitter make sure the next conditions
are met:
- the sensor cable is not to be mounted in
tracks together with high voltage and or
power switching cables;
- use only the standard conductivity cable
with a maximum length of 10 metre;
- mount the transmitter within the distance
of the cable.
NOTE:
The outside earth terminal should be con-
nected to site ground by a large area con-
ductor (e.g. a flat earth strip) for best protec-
tion against interference.
3-2-2. Additional precautions for instal-
lations in hazardous areas
Make sure that the total of capacitancesand
inductances connected to the input termi-
nals of the EXA SC200 do not exceed the
limits given in the certificate.This sets a limit
to the cable and extensions used.
The intrinsic safe version of the EXA SC200
instrument can be erected in Zone 1.
The sensors can be installed in Zone 0 or
Zone 1 if a safety barrier according to the
limits given in the system certificate is used.
3-2-3. Grounding the liquid
In all circumstances, the sensor side of the
measuring loop is grounded to the measu-
ring liquid through one of the electrode con-
tacts in the conductivity cell. The supply and
output signal are isolated to avoid uninten-
tional ground loops.
6

IM 12D7B2-E-H
7
Range selection
3-2-5. Connecting diagram for sensors
2-Electrode system 4-Electrode system
TEMPERATURE
SENSOR
TEMPERATURE
SENSOR
CEL
C= 10/cm
C= 1/cm
C= 0.1/cm
C= 0.01/cm
CEL
e.g.
Use cable WU40/LH...
Max. recommended length 10 m
Use Cells SC41 or SC42
Range selection
* Use of 4-electrode
cell recommended
e.g.
Use cable WU40/LH...
Max. recommended length 10 m.
Use Cells SC49
1 µS/cm 1 mS/cm 1 S/cm 1 µS/cm 1 mS/cm 1 S/cm
C= 10/cm
C= 1/cm
*
*

IM 12D7B2-E-H
3-3. Wiring of power supply
3-3-1. General precautions
Do not activate the power supply yet.First
make sure that the DC-power supply is
according to the specifications given.
WARNING: DO NOT USE ALTERNATING
CURRENT OR MAINS POWER SUPPLY! !
The cable leading to the distributor (power
supply) or safety barrier transports power to
and output signal from the transmitter. Use
a two conductor shielded cable with a size
of at least 1.25 mm2and an outside diame-
ter of 9 to 15 mm. The cable gland supplied
with the instrument accepts these diame-
ters. The maximum length of the cable is
2000 metre. This ensures the minimum ope-
rating voltage for the instrument.
3-3-2. Additional precautions for
installation in hazardous areas
1. Ensure that the total of capacitances
and inductances connected to the termi-
nals of the EXA SC200 do not exceed the
limits given in the certificate of the safety
barrier or distributor.
2. The cable used should preferably have a
BLUE colour or marking on the outside.
3. Grounding:
• If the transmitter is mounted on a
grounded surface (e.g. a metal frame
fixed in the soil) the shield of the 2-wire
cable may NOT be connected to
ground at the distributor.
• If the transmitter is mounted on a non-
conducting surface (e.g. a brick wall) it is
recommended to ground the shield of the
2-wire cable at the distributor end.
4. Installation for EEx ia (sensors in Zone 0
or 1):
Generally, the distributor with input/output
isolation has no external earth connection.If
there is an earth connection on the distribu-
tor and the external connection of the trans-
mitter is connected to ”protective” earth, the
shield of the 2-wire cable may NOT be con-
nected to ”protective” earth at the distributor
too.
3-3-3. Access to terminal and cable
entry
The terminal strip is accessed by removing
the cover from the transmitter as was des-
cribed in § 3-2-4.
Use the left-hand gland to insert the 2-wire
cable to the transmitter.
Connect the supply to the terminals marked
+, - and G as is indicated in the figures on
pages 9 & 10.
3-3-4. Power on
After all connections are made and chec-
ked, the power can be switched on from the
distributor. Observe the correct activation of
the instrument at the display.If for any rea-
son the display does not indicate a value,
consult the trouble shooting section.
8

IM 12D7B2-E-H
9
Wiring diagrams for power supply
General purpose design
Conductivity transmitter
EXA SC200G
NOTE:
The outside earth terminal should be connected to site ground by a large area
conductor (e.g. a flat earth strip) for best protection against interference.
Sensor
Distributor
Output Supply
Dependance of load to supply voltage
1200
1000
800
600
400
200
01718 20 24 40
Ohm
550
Supply voltage (V)
Load resistance (Ω)

IM 12D7B2-E-H
Wiring diagrams for hazardous areas
10
Intrinsically safe design
(CELENEC standard EEX ib [ia] IIC T4)
Conductivity transmitter
EXA SC200S
EEx ib
certified safety
barrier Distributor
Output
Sensor
Elektronic current
Limiting barrier
Vmax: 31.5 V
lmax : 35 mA
Pmax: 0.66 W
Zener barrier with
resistor
Vmax: 28 V
lmax : 93.3 mA
Pmax: 0.66 W
Protective earth
Safe area
Protective earth
Hazardous area Supply
Zone 0 of 1 Zone 1
Eex ib
Certified distributor with
input/output
isolation
Output
Sensor
Shunt zener-
barrier or
supply unit or
isolated
repeater
Vmax: 22 V
Imax : 85 mA
Protective earth
Safe areaHazardous area
Supply
Zone 0 of 1 Zone 1
Intrinsically safe design
(CELENEC standard EEX ib [ia] IIC T4)
Conductivity transmitter
EXA SC200S

IM 12D7B2-E-H
11
4. COMMISSIONING
4-1. Operations overview
MAINTENANCE
Operation by keys
through the closed cover
CAL
DISPLAY
HOLD
Calibration
Show or fix additional values
Switching hold function on/off
5-1
5-2
5-3
Adjusting the output range
Activating the hold function
Temperature compensation
4-2
4-3
4-4
Fine tuning the performance 7
OUTPUT
SET HOLD
TEMPERATURE
SERVICE
COMMISSIONING
Operation by *-key
when cover is removed
SERVICE
Operation by coded
entry from commissioning
Routine Use Chapter
Note: All levels can be protected by a 3 digit passcode. See §7-15.

IM 12D7B2-E-H
Remove cover by releasing 4 screws. Display will show * 0% Display will show *100%
12
4-2. Output range adjustment
1. Access output 2. Adjust low span value 3. Adjust high span value
OUTPUT
SET HOLD
TEMPERATURE
SERVICE
YES NO
YES NO
MODE
.
*
OUTPUT
SET HOLD
TEMP.
SERVICE
ENT
µS/cm
ENT
OUTPUT
SET HOLD
TEMP.
SERVICE
ENT
mS/cm
ENT
Access commissioning menu Adjust value for low span
Select digit to adjust
or decimal point and units
Adjust digit
Confirm adjusted value
ENT
L
*
Return to measurement
select output function
Select OUTPUT
YES
NOTE:
If the output is commissioned to be via a
table this whole item will be skipped! Default
is a linear range.
L
Adjust value for high span
Select digit to adjust
or decimal point units
Adjust digit
Confirm adjusted value
ENT
L
L
MODE
ESCAPE TO MEASURE can be used at any stage to abort operation. WARNING: If the HOLD function is activated the instrument returns with the question HOLD (flashing);
answer YES or NO or MODE again to return to measurement.
MODE

IM 12D7B2-E-H
13
1. What is the output range?
The display will always show the full range of
the instrument from 0-2000 mS/cm.
Maximum resolution is assured by autorang-
ing, where the position of the decimal point
and the measuring units (microSiemens/-
milliSiemens) are moved to best fit the actu-
al value.
For control or recording the current output
can be ranged to a specific part of the total
measuring span. When selecting the
measuring range care must be taken to use
the appropriate conductivity cell. For any
given cell constant there is a defined range
of operation which should not be exceeded.
From the factory the instrument has a linear
output range 0-1 mS/cm in combination
with a cell constant C=0.1 cm-1.
Other linear ranges can be programmed in
this routine. It is also possible to program
non linear output ranges for specific applica-
tions. These are programmed in the service
level, see sections 7-5 and 7-6.
2. Programming a linear output range
A linear output range is programmed by
entering two values:
- 0% the conductivity at the start of the
output range which corresponds
to 4 mA
- 100% the conductivity at the end of the
output range which corresponds to
20 mA.
When programming a range which does not
start at zero conductivity, take care to
respect the minimum value corresponding
to 60% of the maximum value.
3. Example
The EXA SC200 has an output table which
can be programmed to give any non-linear
output characteristic. Activation of this table
is described in §7-5. Once the table is acti-
vated the linear OUTPUT routine will no lon-
ger have any effect and will not be accessi-
ble in the commissioning menu.
Programming of the 21 step table is descri-
bed in § 7-6.
Non-linear outputs are commonly used for
measurements in pure water where high
resolution is required over a small range
combined with trend indication over a larger
range. Common forms of output for these
applications are given in §7-17.
The non-linear output can also be used to
follow a concentration curve for a specific
product. Care must be taken to ensure that
the temperature compensation is also set
up for the measured fluid under representa-
tive conditions. It should also be noted that
conductivity measurements are not specific,
so it can be influenced by impurities present
or changes in the fluid composition.
4. Other possibilities
Programming a percent by weight indication
on the second display line §7-13
4-2. Output range adjustment

IM 12D7B2-E-H
14
*HOLD = Set HOLD function Display shows actual status.
*H.OFF = HOLD not active
*H.ON = HOLD activated
Displa`y shows current setting
4-3. Set up HOLD function
1. Access HOLD routine 2. Activate HOLD function 3. Adjust value to hold
OUTPUT
SET HOLD
TEMPERATURE
SERVICE
YES NO
YES NO
MODE
.
*
OUTPUT
SET HOLD
TEMPERATURE
SERVICE
YES NO
YES NO
MODE
.
*
OUTPUT
SET HOLD
TEMP.
SERVICE
ENT
ENT
HOLD
.
Access commissioning menu
SELECT choice
*
Select SET HOLD
Move pointer to SET HOLD
NO
YES
Activate (de-activate) HOLD
Change setting
Conform setting
NO
YES
Select HOLD fixed or last
Change selection
Confirm selection
NO
YES
*H.FIX = Hold fixed value
*H.LST = Hold last value
Adjust fixed value
Select digit to adjust
Adjust value of digit
Accept value
Return to measurement
ENT
L
L
MODE
ESCAPE TO MEASURE can be used at any stage to abort operation. WARNING: If the HOLD function is activated the instrument returns with the question HOLD (flashing);
answer YES or NO or MODE again to return to measurement.
MODE

IM 12D7B2-E-H
15
1. What is HOLD?
HOLD is a function freezing the output sig-
nal temporary, during normal maintenance,
preventing all sorts of alarming situations to
occur.
Two possibilities are generally used:
a .Keeping the output at the LAST value just
before the start of maintenance. This can
only be used when a recorder is connec-
ted.
b. Keep the output at a preset FIXED value
which will not cause any of the alarms to
go off or any controlling action to be
taken. This is the preferred situation when
dealing with Conductivity-control sys-
tems.
2. How does it work?
The HOLD-function has to be activated from
the *-menu before it can be used.
The EXA SC200 will keep the output frozen
during the following events:
- Access to the *-menu.
- Access to the calibration mode.
- Switching it from the MODE-menu.
HOLD is signalled in the display by a special
field.
The operator is prompted to switch HOLD
on or off before returning to normal mea-
surement.
3. Example
In a storage tank the concentration of sodi-
um hydroxide (caustic soda) has to be kept
at 5% . The mixing process is controlled by
a conductivity transmitter and electro-mag-
netic valves.
During maintenance of the conductivity cell
or the transmitter the HOLD function is acti-
vated to keep the mixing process from was-
ting precious chemicals to the sewer.
The HOLD function is set for a fixed output
so that the dosing valves will not be activa-
ted.
4. Time out
Hold will be de-activated after 20 minutes if
no key is pressed. To cancel this function
see 7-8.
4-3. Set up HOLD function

ESCAPE TO MEASURE can be used at any stage to abort operation. WARNING: If the HOLD function is activated the instrument returns with the question HOLD (flashing);
answer YES or NO or MODE again to return to measurement.
IM 12D7B2-E-H
16
TEMP = Temperature compensation function NaCl = Automatic temperature compensation The setting of the temperature coefficient is done
by adjusting a conductivity value, at process tem-
perature, to the conductivity value that was meas-
ured at reference temperature
4-4.Temperature compensation
1. Access temperature
compensation routine 2. Select automatic NaCl temperature compensation 3 Select temperature coefficient
compensation
OUTPUT
SET HOLD
TEMPERATURE
SERVICE
YES NO
YES NO
MODE *
OUTPUT
SET HOLD
TEMPERATURE
SERVICE
YES NO
YES NO
MODE *
OUTPUT
SET HOLD
TEMP.
SERVICE
ENT
ENT
TEMP. MAN
..
mS/cm
Access the maintenance menu
Select temperature compensation
function
*
Select temperature compensation
routine
Move pointer to TEMP
NO
YES
Select automatic compensation
Change displayed selection
Confirm selection
NO
YES
NOTE:
1. If NaCl is chosen the temperature compensa-
tion will be according to NaCI solutions.
2. If *NaCl and *T.C. do not appear, this indicates
that Matrix compensation is selected in service
code 13.
Adjustment of the conductivity value
Select digit to adjust
Adjust manual temperature
Confirm adjusted value
ENT
L
L
Error E2 indicates that the temperature coefficient
is less than-10%/°C or more than +10%/°C.
NOTE:
Direct setting of the compensation factor is possible.
Refer to §7-12.
MODE