Honeywell ACM 150 Manual To Installation, Operation, And Maintenance page 112

ACM 150
Figure 67. Background, S/N, and drift
Acquire background
You can obtain a background spectrum on demand by selecting 'Acquire
Background'. As shown in
evaluation.
In this mode it is also possible to 'Save New Factory Background' Scan', which
would replace the prior reference background.
NOTE
Do not save a new factory background unless you are requested to do so by
your HA service technician or application chemist. There should be a valid
purpose for updating this reference.
Figure 68, the background spectrum is displayed for
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