62
MAN0530 Issue 10 - 11/09 Searchline Excel
2104M0506
5. PROBLEM SOLVING
Fault/Problem Causes Remedies
Electrical installation 1)Checkthatthe+24Vsupplyisreachingtheunit.
problem Voltageattheunitshouldbebetween+18Vand+32V.
2) Check cables and connections to the unit, especially
the 4-20mA loop connections.
3) Check that the unit has the correct type of 4-20mA
output for use with the controller that it is connected to.
Heavy contamination of Check the Transmitter and Receiver windows for
optics build up of contamination. Clean the windows if
required. Re-zero unit.
Very low visibility along 1) Check that the Transmitter can be seen from the
beam path due to dense Receiver. If Transmitter can be seen, even with some
fog, blizzard or difculty,lowvisibilityisunlikelytobetheproblem.
sand-storm 2) If the Transmitter cannot be seen from the Receiver,
conditions very low visibility could be the problem. Wait until
visibility improves and verify that the unit then returns
to operational status.
Output is 2.5mA. Beam path is blocked Check that the beam path is clear from the Transmitter
(BEAM BLOCK) to Receiver. Remove any obstruction if present.
Transmitter or Receiver 1) Connect SHC1 Interrogator to unit and check signal
misaligned levels.
2) If signal levels are low, use the telescope and SHC1
Interrogator to optimise Receiver alignment.
3) If signal levels remain low after re-aligning
Receiver, check the Transmitter alignment using
the telescope.
4) Re-zero the unit after alignment. See Appendix
A.5.3.4.
Output is 3mA Heavy contamination of Check the Transmitter and Receiver windows for
(LOW SIGNAL) optics build up of contamination. Clean windows if required.
Re-zero the unit.
Transmitter or Receiver 1) Use the telescope and Interrogator to optimise
misaligned Receiver alignment.
2) If signal levels remain low after re-aligning
Receiver, check the Transmitter alignment using
the telescope.
3) Re-zero the unit after alignment. See Appendix
A.5.3.4.
Output is 2mA Unit has been inhibited by Release output from INHIBIT state using SHC1
(INHIBIT) the Interrogator Interrogator.
Unit executing power-up 1) Wait for 1 minute. When power-up routine is
routine completed satisfactorily the unit’s output should
exit the INHIBIT state.
2) If unit remains in INHIBIT,checkthe+24Vsupply
isreachingtheunit.Ifthevoltageisbelow+18Vor
isuctuatingaboveandbelow+18V,theunitmay
be being prevented from completing power-up.
(This is an electrical installation problem.)