Heath Consultants Optical Methane Detector (OM) - Manual (Page 21)

21
LIGHT:
In this position, numbers in the range from 0 to -1200 are dis-
played, indicating the amount of light reaching the detector with
the lower numbers (more negative) indicating the highest light
levels. This is illustrated in the following figure.
The calibration data sheet shows the number range typical for
this system when the lenses are clean. The light level can be
decreased by the amount of accumulated water and dirt on the
lenses. This is normal and the system will remain in calibration
and maintain its sensitivity to methane. If the light level goes
below a low limit, the LOW LIGHT alarm will be activated at
the level indicated by the data sheet that was shipped with your
instrument. At that point it may be necessary to clean the lenses.
the HOLD mode. The following picture shows the OMD in the
HOLD mode.
PRESENT
0.0
MAXIMUM
16.6
SETPOINT
30.0
10 PPM
0 PPM
Push Display to Continue
LIGHT
LEVEL
-706.2
-706.5
-707.1
-707.4
-706.8
Push
Display
To Exit
O
PERATING
P
ROCEDURES