WIKA T12 - Handbuch (Seite 33)

GB
3211517.07
07/2010
GB/D
WIKA operating instructions temperature transmitter T12 33
11. Faults
11. Faults
Fault-tree
l = 0 mA
Current loop
disconnected
Wrong polarity of
the supply voltage
Transmitter not
connected
Wrong sensor type
Wrong 2-, 3- or
4-wire connection
Wrong
temperature range
Wrong
compensation
Sensor =
TE
Sensor =
RTD
l > 20 mA
l < 4 mA
4 mA < l < 20 mA
but wrong values
Current value is okay, but
temperature drift while
transmitter is heating up or
cooling down
Process
temperature out of
range
Wrong sensor
connection
Sensor burnout or
short circuit
Wrong transmitter
configuration
Capacitive or
inductive coupling
over the sensor
Capacitive or
inductive coupling
over the loop
Wrong polarity of
thermocouple
Loop resistance too high
Electromagnetic
interferences
Linearization error for
sensor / transmitter
Current value falls while
measuring temperature rises
(and vice versa)
Current value is okay at low
values, but too low at higher
temperatures
Current value is unstable and
changes within seconds
Temperature values only
correct at the measuring limits