Endress+Hauser Liquisys M CLM223/253, Operating Instructions Manual

Page: 75 / 112

Liquisys M CLM223/253 Diagnostics and troubleshooting
Hauser 75
7.3 Process specific errors
Use the following table to locate and correct errors.
Error Possible cause Tests and / or remedial measures Equipment, spare parts, personnel
Display deviates from
reference measurement
Calibration faulty Calibrate instrument according to
chapter "Calibration".
Calibration solution or sensor certificate
Sensor soiled Clean sensor. See chapter "Cleaning conductivity
sensors".
Incorrect temperature measurement Check temperature value on instrument
and reference unit.
Temperature measuring instrument,
precision thermometer
Incorrect temperature compensation Check compensation method (none /
ATC / MTC) and compensation type
(linear/substance/user table).
Please note: transmitter has separate
calibration and operating temperature
coefficients.
Reference instrument calibration
faulty
Calibrate reference instrument or use
calibrated instrument.
Calibration solution, operating
instructions of reference instrument
Incorrect ATC setting on reference
instrument Compensation method and
compensation type must be identical on
both instruments.
Operating instructions of reference
instrument
Polarization error Use suitable sensor:
• Use larger cell constant.
• Use graphite instead of stainless steel
(check resistance).
Measuring range tables e.g. in FA
"Conductivity" or technical data of
conductivity sensors
Incorrect line resistance in field A6 Enter correct value CYK71: 165  /km
Implausible measured
values in general:
– continuous measured
value overflow
– measured value always
000
– measured value too low
– measured value too
high
– measured value frozen
– incorrect current
output value
Short circuit / moisture in sensor Check sensor. See chapter "Checking inductive
conductivity sensors".
Short circuit in cable or junction box Check cable and junction box. See chapter "Checking extension cable
and junction box".
Interruption in sensor Check sensor. See chapter "Checking inductive
conductivity sensors".
Interruption in cable or junction box Check cable and junction box. See chapter "Checking extension cable
and junction box".
Incorrect cell constant setting Check cell constant. Sensor nameplate or certificate
Incorrect output assignment Check assignment of measured values to
current signals.
Incorrect output function Check 0-20 / 4 -20 mA selection and
curve shape (linear /table).
Air cushion in assembly Check assembly and installation.
Grounding short on or in device Measure in insulated container Plastic container, calibration solutions
Transmitter module defective Test with new module. See chapter "Spare parts".
Impermissible instrument operating
state (no response to key actuation) Switch instrument off and back on. EMC problem: check grounding and line
routing if problem persists or call E+H
Service to test.
Incorrect temperature
value
Incorrect sensor connection Verify connections using connection
diagram; three-wire connection
mandatory.
Connection diagram in chapter "Electrical
connection"
Measuring cable defective Check cable for interruption/short
circuit/ shunt. Ohmmeter
Incorrect temperature sensor type Select temperature sensor type on
instrument (field B1).