Problem
Possible cause
Tests and / or remedial measures Equipment, spare parts, personnel
Display dark, but LED(s)
active
Central module defective
(Module: LSCH/LSCP)
Replace central module
On-site diagnosis by E+H Service
(LSCxx module required)
Display on, but
– no change in display
and / or
– instrument cannot be
operated
– Instrument or module in
instrument incorrectly installed
COM 223: Reinstall
module
COM 253: Reinstall display
module
Carry out using installation -
diagrams, Chap. 8.4.1 and 8.5.1
– Impermissible operating system
state
Switch instrument off and back on
Possible EMC problem: if problem
persists, call E+H Service to have
installation checked
– Missing pixels in
display
– Conductive rubber soiled
Replace LSCxx module
Clean conductive rubber and
printed conductor
only in emergency, with alcohol
and glass fibre brush
– Contact pressure too low
Lay paper strips in frame
Only in emergency, better:
replace LSCxx
Instrument gets hot
– Incorrect voltage / too high
Compare mains voltage and rating
on nameplate
Correct voltage setting, see Chap.
8.4.1 / 8.5.1
– Power unit defective
Replace power unit
Diagnostics only possible through
E+H Service
Measured value O
2
and / or
measured value
temperature incorrect
– Transmitter module defective
(Module: MKO1 / MKO 5).
First carry out tests and
measures acc. to Chapter 7.3 to
make sure that the error does not
lie with the sensor or cabling.
Measuring inputs test MKO 1:
– Connect substitute resistances
for oxygen and temperature,
see Chapter 8.8.1
Measuring inputs test MKO 5:
(WX/WS)
If test negative: Replace module
(check variants), Carry out using
the explosion drawings Chap. 8.4.1
and 8.5.1.
only possible with intact sensor as
digital data transfer sensor <->
instrument
If test positive: check peripherals
once more.
– Incorrect sensor current
Sensor current readable in the
display in measurement mode by
pressing “+” key 3 x
Display in nA. Nominal value in air
for 20 °C and 1013 hPa: 290 nA
Pressure value incor-
rect / unreadable
– Defective pressure sensor
Module MKO1 defective
Module MKO5 defective
Pressure readable in field S 11.
Caution: The absolute air pressure
is displayed.
– No pressure sensor available
From introduction -WX/WS:
- WX/WS always with pressure
sensor
- DX/DS with MKO1 is always
without pressure sensor
Current output,
incorrect current
– Not calibrated correctly
Test with built-in current simulation,
connecting mA meter directly to
current output.
Check whether 0–20 mA or
4–20 mA has been selected
If simulation value is incorrect:
recalibration at factory or new
LSCxx module required.
If simulation value is correct: check
current loop for load and shunts.
– Load excessive
– Shunt / short-circuit to frame in
current loop
– Incorrect mode of operation
No current output signal
– Current output stage defective
(module: LSCH/LSCP)
Test with built-in current simulation,
connecting mA meter directly to
current output. For safety reasons
completely disconnect the auxiliary
power output beforehand.
If test negative:
Replace central module
(using correct variant)
Additional relays do not
work
– COM 253: ribbon cable
Pos. 320 loose or defective
Make sure ribbon cable is properly
connected, replace cable if nec.
See spare parts for COM 253
Only 2 additional relays
can be used
– Relay module LSR1-2 with 2
relays installed
Convert to LSR1-4 with 4 relays
Operator or E+H-Service
Additional functions
(S packet) missing
– No or incorrect release code
used
When upgrading: check that the
correct serial number was used
when ordering the S packet
Handling by E+H sales
– Incorrect serial number of the
LSCH/LSCP module
Check that the serial on the
nameplate agress with the SNR
LSCH/LSCP (Field E113)
For the S packet, the serial number
of the LSCH/LSCP module is
decisive.
– Changed product strategy
From introduction WX/WS:
- WX/WS always with pressure
sensor
- DX/DS always without pressure
sensor
for DX/DS: Use location height
setting
Diagnostics and corrective maintenance
Liquisys M COM 223 / 253
60
Hauser
