Problem Solving - Honeywell Searchline Excel Cross-Duct Technical Handbook

MAN0889_Issue 3_03/13
The majority of gas detector problems/faults can be diagnosed and corrected using the installation kit.
The installation kit includes:
• SHC1 Handheld Interrogator
• set of functional test filters
An electrical multimeter is also useful when diagnosing electrical/wiring problems.
Refer to the troubleshooting tables in this chapter for a list of problems, possible causes and actions.
Caution: Searchline Excel Cross-Duct does not contain any user serviceable parts. Do not open or
disassemble the Transmitter and Receiver unit, or the Heated Reflector Panel. The warranty
of units which have been opened is invalidated.
Note: THE INFRARED BEAM IS INVISIBLE AND EYE SAFE.
RS485 Modbus signal errors may occur when Excel is connected via a DXI00 (M) Termination Unit and is
interrogated/commanded from a network control centre. For troubleshooting these issues refer to the DX100
Series Termination Units Technical Handbook.
If, after following the recommendations in this section, the problem persists, please make available the following
information before contacting Honeywell Analytics:
• Installation Check Sheet
See Chapter 3.
• Any error message
Displayed on the Handheld Interrogator screen.
• Any error code
Displayed on the Handheld Interrogator screen.
Fault/Problem Causes
No mA output Electrical installation problem
Unit is in FAULT condition
Output is 0mA
Beam block
(nominal)
Heavy contamination of optics
Output is 2.5mA.
Beam path is blocked
(BEAM BLOCK)
Output is 3mA
Heavy contamination of optics
(LOW SIGNAL)

5. Problem Solving

Searchline Excel Cross-Duct Technical Handbook
Remedies
1) Check that the +24V supply is reaching the unit. Voltage at the
unit should be between +18V and +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
sink/source for use with the controller that it is connected to.
Connect the SHC1 Interrogator to the unit and use its
DIAGNOSTIC menu options to ascertain the reason for the FAULT
report.
Check that beam path is clear from the Transmitter and Receiver
to the Reflector. Remove any obstruction if present.
Check the Transmitter and Receiver windows and the Heated
Reflector Panel for build up of contamination. Clean the windows
if required. Re-zero unit.
Check that beam path is clear from the Transmitter and Receiver
to the Reflector. Remove any obstruction if present.
Check the Transmitter and Receiver windows and the Heated
Reflector Panel for build up of contamination. Clean the windows
if required. Re-zero unit.
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