Honeywell Searchline Excel Open-Path Technical Handbook page 109

MAN0530 Issue 09 October 03
2104M0506
APPENDIX A - HANDHELD INTERROGATOR
Alignment
This starts the alignment process.
The following message is displayed:
This message displays the system output and reference signal values.
where: A bar graph representing the current signal magnitude - SIG:
A bar graph representing the target signal - TGT:
Important Notes:
1) The overall objective of alignment is to maximise the SIG level. Maximised SIG
corresponds to optimal alignment.
2) The Instrument Assisted Alignment (IAA) system only allows Excel to be initialised if the
SIG level is greater than or equal to the TGT level when Enter is pressed.
3) The smallest TGT signal level that is initially set will be equivalent to 70% (0.700) of the
signal expected for the installation's path length.
4) The TGT level will increase gradually if the current SIG level is larger than the TGT level.
The TGT signal level only ever increases. If the current SIG level falls below the TGT
level, TGT will remain at its previous highest value. In order to initialise the gas detector
the SIG level must be brought back above the TGT level.
5) If the SIG level is less than 50% of the expected level, the bar graphs are not displayed.
Instead both SIG and TGT levels are displayed as numbers.
Options
The approach to mechanical alignment depends on the type of alignment telescope and mounting
initially used to set up the Excel gas detector, also see Chapter 3.
Bayonet-style Trident-type telescope assembly
If this type of alignment telescope was used with a Trident-type Excel gas detector, there is no
need to further optimise the alignment using the SHC1 Handheld Interrogator.
When the SIG and TGT bar graphs are displayed on the SHC1 screen, SIG will always be
greater than TGT and installation can proceed to the next stage by pressing Enter and following
step 12.
Press Enter to
Align Unit
SIG:
MAX:
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