Endress+Hauser Liquiphant M FTL50 Serie Mode D'emploi page 63

Fault Reason
Does not switch No power
Faulty signal line
Faulty electronic insert
- FEL51 connected directly to L1 and N
Density of liquid too low
Fork encrusted
Fork corroded
(Indication on FEL: red/yellow flashes,
FEL58: green flashes 0.3 Hz)
FEL51: Internal resistance of connected
relay too large
FEL51: Holding current of connected relay
too low
FEL54: Contacts welded together
(after short-circuit)
Switches Min-/Max- fail-safe mode set wrongly
incorrectly
Sporadic faulty Thick heavy foam,
switching very turbulent conditions,
foaming liquid
Extreme RFI
Extreme vibration
Water in housing
FEL52: Output overloaded
Switches FEL57, behaviour during switch-on test
incorrectly after (functional test)
power failure
Endress+Hauser
Remedy
Check power
Check signal line
Exchange
- always connect FEL51 via external load
Set density to > 0.5 at electronic insert
Clean fork
Exchange fork and process connection
Connect suitable relay
Connected resistor in parallel with relay
Exchange FEL54; put fuse in contact circuit
Set correct mode at electronic insert
Mount Liquiphant in bypass
Use screened cable
Decouple, damp, turn fork 90°
Screw cover and cable gland tight
Reduce load,(cable) capacitance
Observe switching behaviour of FEL57;
After power failure blockplant control
for up to 45 s
en - Trouble-shooting
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