26
System Malfunctions
– continued –
Fault finding list for troubleshooting system malfunctions: Limiters 1 – 4
Depending on the indication of the malfunction press and hold down key 1 or 2 or 3 or 4.
LED 1 is flashing slowly
Fault:
The
limiter
(level electrode / temperature transmitter) and
the control unit
cannot
communicate.
Remedy:
Check 24 V bus supply, wiring, configuration of the low level electrodes (wire links), node
ID, baud rate setting and terminating resistor. If modifications have to be made, switch off
mains voltage and switch it on again after about 5 seconds.
Fault:
The
limiter
and the
controller
cannot communicate. The fault occurs at long intervals.
Remedy:
There is a source of interference in the surrounding area. To suppress interferences provide
contactors and actuators with RC combinations in accordance with the specifications of
the manufacturer. Take action against high frequency interference.
LEDs 2 and 3 are flashing slowly
Fault:
The temperature in the terminal box of the level electrode or the temperature transmitter
exceeds the max. limit.
Remedy:
Check installation of electrode and insulate electrode flange against thermal radiation.
Check place of installation of the temperature transmitter.
LED 3 is flashing slowly
Fault:
One or more of the self-checking routines detected a malfunction, which means that the
electronic insert of the level electrode or the temperature transmitter is defective.
Remedy:
Replace electronic insert.
Fault:
The temperature sensor is defective (parting of a cable, short circuit).
Remedy:
Check temperature sensor and supply cables (see Installation Instructions TRV 5-40),
replace measuring element of the temperature sensor.
