Honeywell SEARCHLINE EXCEL PLUS Technical Manual page 83

Fault / Problem
4–20 mA output is in fault
4–20 mA output is <= 1 mA
4–20 mA output is 2 mA
(INHIBIT)
4–20 mA output is 3 mA
(WARNING)
Description
4–20 mA loop wiring has been disturbed
Detector is in Fault
Beam is blocked
Transmitter or Receiver is misaligned
Electrical installation problem
Heavy contamination of optics
Very low visibility along beam path due
to dense fog, blizzard or sand-storm
conditions
Unit has been inhibited by Fixed Platform
App
Unit is executing power-up routine
Heavy contamination of optics
Transmitter or Receiver is misaligned
Searchline Excel™ Plus / Searchline Excel™ Edge – Technical Manual
Chapter 11 Problem Solving
Remedial Action
Check 4–20 mA loop is correctly connected and
terminated
Reset the fault using the Fixed Platform App or HART
If the fault persists, power cycle the detector
If the fault still persists, contact Authorized Service
Run diagnostics with the Fixed Platform App
Check that beam path is clear from the Transmitter to
the Receiver. Remove any obstruction if present.
1) Connect to the Fixed Platform App and check the
signal levels
2) If signal levels are low, use the alignment scope and
Fixed Platform App to optimise Receiver alignment
3) If signal levels remain low after re-aligning Receiver,
check the Transmitter alignment
4) Re-zero the unit after alignment
1) Check that the +24 V supply is reaching the unit.
Voltage at the unit should be between +18 V and +32 V
2) Check cables and connections to the unit, especially
the 4-20 mA loop connections
3) Check that the unit has the correct type of 4–20 mA
output for use with the controller that it is connected to
Check the Transmitter and Receiver windows for
build up of contamination. Clean the windows if
required. Re-zero unit.
1) Check that the Transmitter can be seen from the
Receiver. If Transmitter can be seen, even with some
difficulty, low visibility is unlikely to be the problem.
2) If the Transmitter cannot be seen from the Receiver,
very low visibility could be the problem. Wait until
visibility improves and verify that the unit then returns
to operational status.
Release output from INHIBIT state using Fixed Platform
App
1) Wait for 1 minute. When power-up routine is
completed satisfactorily the unit's output should
exit the INHIBIT state
2) If unit remains in INHIBIT, check the +24 V supply
is reaching the unit. If the voltage is below +18 V or
is fluctuating above and below +18 V, the unit may
be being prevented from completing power-up.
(This is an electrical installation problem.)
Check the Transmitter and Receiver windows for
build up of contamination. Clean the windows if
required. Re-zero unit.
1) use the alignment scope and the Fixed Platform App
to optimise Receiver alignment
2) If signal levels remain low after re-aligning the
Receiver, check the Transmitter alignment
3) Re-zero the unit after alignment
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