Endress+Hauser liquiphant S FTL 70 Manual página 59

Fault Reason
Does not switch No power
Faulty signal line
Faulty electronic insert
– FEL 51 connected directly to
L1 and N
Density of liquid too low
Fork encrusted
Fork corroded
(Indication on FEL: red/yellow flashes,
FEL 58: green flashes 0.3 Hz)
FEL 51: Internal resistance of
connected relay too large FEL 51: Holding current of
connected relay too low
FEL 54: Contacts welded together
(after short-circuit)
Switches Min- / Max- fail-safe mode set
incorrectly wrongly
Sporadic faulty Thick heavy foam,
switching very turbulent conditions,
foaming liquid
Extreme RFI
Extreme vibration
Water in housing
FEL 52: Output overloaded
Switches FEL 57,
incorrectly after Behaviour during switch-on test
power failure (functional test)
Endress+Hauser
Remedy
Check power
Check signal line
Exchange
– always connect FEL 51 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 FEL 54; 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
FEL 57; After power failure block
plant control for up to 45 s
e Trouble-shooting
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