Endress+Hauser Liquisys M CLM223 - Page 86

Diagnostics and troubleshooting Liquisys M CLM223/253
86 Endress+Hauser
Error Possible cause Tests/remedial action Tools, spare parts
Incorrect
temperature value
Incorrect sensor
connection
Check connections using wiring
diagram. Three-wire connection
always required.
Wiring diagram in
"Electrical connection"
section
Measuring cable
defective
Check cable for interruptions/
short-circuit/shunt.
Ohmmeter
Incorrect sensor type Set type of temperature sensor at
the device (field B1).
Fluctuations in
measured value
Interference on
measuring cable
Connect cable shield as per wiring
diagram
See the "Electrical
connection" section
Interference on signal
output cable
Check cable routing, possibly
route cable separately
Route signal output and
measuring input lines
separately
Interference potential in
medium
Eliminate source of interference
or ground medium as close as
possible to sensor.
Electromagnetic
interference on signal
lines with conductive
sensors
Use shielded cables and ground
the cable shield
Controller or timer
cannot be
activated
No relay module
available
Install LSR1-2 or LSR1-4 module
Controller/limit
contact does not
work
Controller switched off Activate controller See fields R2xx
Controller in operating
mode "Manual off"
Select "Auto" or "Manual on" mode Keyboard, REL key
Pickup delay setting too
long
Switch off or shorten pickup delay
time
See fields R2xx
"Hold" function active “Auto hold” for calibration,
“Hold” input activated;
“Hold” active via keyboard
See fields S2 to S5
Controller/limit
contact works
continuously
Controller in operating
mode "Manual on"
Select "Auto" or "Manual off" mode Keyboard, REL and AUTO
keys
Dropout delay setting too
long
Shorten dropout delay time See fields R2xx
Control loop interruption Check measured value, current
output value, actuators, chemical
supply
No conductivity
current output
signal
Cable disconnected or
short-circuited
Disconnect cable and measure
directly at device
mA meter 0–20 mA
Output defective See the "Device-specific errors"
section
Fixed conductivity
current output
signal
Current simulation active Switch off simulation. See field O3
Impermissible operating
state of processor system
Disconnect line voltage for
approx. 10 seconds
Possibly EMC problem: if
problem persists, check
grounding and wire
routing.
Incorrect current
output signal
Incorrect current
assignment
Check current assignment: 0–20
mA or 4–20 mA?
Field O311
Total load in the current
loop too high (> 500 Ω)
Disconnect output and measure
directly at device
mA meter for 0–20 mA
DC
EMC (interference
coupling)
Disconnect both output cables and
measure directly at device
Use shielded cables,
ground shields at both
ends, where necessary
route cable in another
cable duct