Heath Consultants Optical Methane Detector (OM) - Manual (Page 28)

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Chapter IV
ALIGNMENT PROCEDURE
In order for your OMD to function properly, it is crucial that
the optical path be aligned properly. The OMD components
are pre-aligned at the factory and should not require re-align-
ment when the system is installed on the vehicle. It is, how-
ever, important that the u-bolts be attached and tightened such
that they do not bow the support rod. The u-bolts should be
tight enough to hold the OMD crossbar securely in place, but
not so tight as to distort the crossbar. If that happens, re-
alignment may be required. This alignment can be done fairly
easy in the field by following this procedure.
There are no adjustments to be made inside the Receiver or the
Light Source. The design relies on the mechanical tolerances
to place the components in the proper place. Final alignment
makes use of the external alignment screws on the Light
Source and the Receiver.
To be aligned, first clean the light source and receiver input lenses.
Turn on the system power and press “Display Function” on the
display until “LIGHT LEVEL” appears. With the light source on
and the light path clear of all obstacles, this number should be close
to the number that appears on your data sheet (+ or – 20). If this
number differs by more than 50 (closer to zero), it is a good indica-
tion that your OMD needs to be re-aligned.
Lamp Alignment:
The alignment process starts by using the alignment screws on the
Light Source to visually center the light beam on the Receiver lens.