English (GB)
25
11. Fault finding
The instrument is maintenance-free, repairs can only
be carried out in the factory.
The following table provides you with short
guidelines for possible faults caused by missing or
faulty cables or faults in the sensor system.
Fault
Cause
Remedy
1.
No display after
switching-on.
a) Power supply disconnected.
Connect the power supply.
2.
SP (setpoint) LED cannot
be selected.
a) Code 2001 activated.
Delete code 2001.
3.
Stop (controller stop) LED
cannot be selected.
a) Controller configuration has not
been made.
Carry out controller configuration.
4.
Code numbers cannot be
selected.
a) Enable code 0086 has been
deleted; instrument is protected
against unauthorised
operation.
Enter enable code 0086 again. See
section
.
Conex
®
DIS-D
Fault
Cause
Remedy
1.
Measured-value display
unsteady.
a) Interferences on lines from
electrode/measuring cell.
Check the screen/cable.
b) Connection cables/plugs
between measuring cell and
Conex
®
DIS interrupted or
moist.
Check the cables, and replace if
necessary.
c)
Sensor/electrode faulty.
Replace the sensor/electrode. Check
the potentiostatic control voltage, 100
mV, between terminal M (20) and B/R
(21) with operational/connected
measuring cell. Use a voltmeter.
2.
Display at full-scale value. a) Connection cable between
electrode/measuring cell and
instrument amplifier
interrupted.
Check cable, and establish
connection.
b) Measuring electrode faulty
Replace the measuring electrode.
3.
Alarm during calibration.
a) Measuring cell/electrodes
contaminated or blocked by
deposits.
Remove the electrodes and clean the
measuring and counter electrodes
(see also installation and operating
instructions of the measuring cells).
4.
Sensor value too small
compared to reference.
a) Incorrect calibration.
Repeat the calibration.
b) pH value for measurement
higher than with calibration
(only with chlorine).
Keep pH value constant for
measurement and calibration.
5.
Sensor value too high
compared to reference.
a) Incorrect calibration.
Repeat the calibration.
b) pH value for measurement
lower than with calibration (only
with chlorine).
Keep the pH value constant for
measurement and calibration.