Simple Fault Finding - ABB 268D/V Operating Instruction

SIMPLE FAULT FINDING (HART)
This part is applicable only for a quick fault finding in the case that the Hand Held Terminal or the P.C. Configurator Package
are not available.
If the transmitter does not appear to be working satisfactory, carry out the following fault finding checks before contacting your
nearest Service Centre.
If the instrument is to be returned for repair, ensure that it is adequately packed using the original polystyrene box or high density
chip foam: the trouble sheet/returning form should be sent with the instrument, filled in all its parts. If the transmitter needs
to be dismantled follow the procedures as described in the previous section.
WARNING : If the transmitter forms part of a control loop, the plant must be placed under local manual
control while the instrument is examined or taken out of service. Take all precautions to avoid damages caused
by pressure or dangerous fluids release.
Equipment needed
Voltmeter , milliammeter (0 to 100 mA d.c.), solvent contact cleaner.
High, Low or Irregular Output
Start (power off)
Check the transmitter
power supply (*)
OK
Check for trapped gas
in liquid lines and liquid
in dry lines
OK
Check for sediment
in process flange (**)
OK
Disconnect sensor
connector from the
electronic circuit.
Clean connector,
Reassemble, switch on
and check instrument
operation
Faulty
Fit replacement
electronic circuit
Still faulty
Fit replacement
transducer assembly
Stop
(*) If the source of the problem is suspected to be the power supply, check it by disconnecting the wires from the transmitter
and testing the volts available at the wires.
(**) If there are sediments in process flanges they must be cleaned, if inevitable flanges have to be removed. Before reassembly
pay attention to the O-ring: Teflon O-ring probably requires to be substituted. Refer to dismantling and reassembly section
for these operations.
- 22 -
Repair or replace
Faulty
power supply
Remedy
Present
Clean out
Present
Stop
OK
Stop
OK
Stop
OK
No output
Start (power off)
Check the transmitter
power supply (*)
OK
Clean connectors.
Reassemble, switch on and
check instrument operation
Faulty
Fit replacement
electronic circuit
Still faulty
Fit replacement
transducer assembly
Stop
WARNING -
repaired, the faulty unit/assembly must be replaced by an
equivalent unit/assembly.
Repair or replace
Faulty
power supply
OK
Stop
OK
Stop
If the transmitter needs to be