Fault Finding And Repairs - Endress+Hauser iTEMP RTD TMT 187 Mise En Service

Temperature head transmitter

Fault finding and repairs

9.3 Fault finding and repairs
Trouble shooting on RTDs (Pt100/Pt500/Pt1000/Ni100)
Fault
≥
Current ( 21 mA)
Incorrect or inaccurate measured
value
Trouble shooting for thermocouple connection (TC)
Fault
≥
Current ( 21 mA)
Incorrect or inaccurate measured
value
Cause
Sensor defective
Incorrect RTD connection
Incorrect 2 wire connection
No power supply on the 2 wire
connection
Head transmitter defective
Sensor is incorrectly installed
Heat dissipation via sensor
Sensor connection (2 wire)
Cause
Incorrect sensor connection
Sensor defective
Incorrect 2 wire connection
(current loop)
No power supply on the 2 wire
connection
Head transmitter defective
Sensor is incorrectly installed
Heat dissipation via sensor
Fault due to the thermo wire
welded to the well (interference
voltages incurred)
9 Fault finding
Action/cure
Check sensor
Connect the cables correctly
(see connection diagram)
Connect the cables correctly
(polarity, see terminal layout)
Check current loop; the supply
should be >8 V
Replace head transmitter
Reinstall sensor correctly
Monitor sensor installation posi-
tioning
Monitor sensor connection
Action/cure
Connect the cables correctly
(polarity, see terminal layout)
Check sensor
Connect the cables correctly
(polarity, see terminal layout)
Check current loop; the supply
should be >8 V
Replace head transmitter
Reinstall sensor correctly
Monitor sensor installation
positioning
Please use a sensor in which the
thermo wire in not welded
29