Faults - WIKA TR10-0 Mode D'emploi

10. Faults

10. Faults
Faults
No signal/line break
EN
Erroneous measured
values
Erroneous measured
values (too low)
Erroneous measured
values and response
times too long
Erroneous
measured values (of
thermocouples)
Indication of the
measured value
jumps
Corrosion
Signal interference
CAUTION!
If faults cannot be eliminated by means of the measures listed above, the
instrument must be shut down immediately, and it must be ensured that signal
is no longer present, and it must be prevented from being inadvertently put back
into service. In this case, contact the manufacturer.
If a return is needed, follow the instructions given in chapter 11.2 "Return".
20
Causes
Mechanical load too high or
overtemperature
Sensor drift caused by
overtemperature
Sensor drift caused by chemical
attack
Entry of moisture into cable or
measuring insert
Wrong mounting geometry, for
example mounting depth too
deep or heat dissipation too high
Deposits on the sensor or
thermowell
Parasitic voltages (thermal
voltages, galvanic voltage) or
wrong equalisation line
Cable break in connecting cable
or loose contact caused by
mechanical overload
Composition of the medium
not as expected or modified
or wrong thermowell material
selected
Stray currents caused by electric
fields or earth loops
Earth loops
WIKA operating instructions models TR10-0, TC10-0 (Ex d)
Measures
Replacement of the sensor or the
measuring insert with a suitable version
Replacement of the sensor or the
measuring insert with a suitable version
Use of a suitable thermowell
Replacement of the sensor or the
measuring insert with a suitable version
The temperature-sensitive area of the
sensor must be inside the medium, and
surfaces must be ungrounded
Remove deposits
Check polarity
Use of a suitable equalisation line
Replacement of the sensor or
measuring insert with a suitable design,
for example fitted with strain relief or a
thicker conductor cross-section
Analyse medium and then select a
more-suitable material or replace
thermowell regularly
Use of screened connecting cables,
increase in the distance to motors and
power lines
Elimination of potentials, use of
galvanically isolated transmitter supply
isolators or transmitters