Heath Consultants Remote Methane Leak Detector Intrinsically Safe (RMLD-I) - Manual (Page 22)

Fig. 3-7
5. Press the UP button to initiate the self-test. The number 255 will then be
displayed.
6. When the OK icon is displayed, the instrument passed the self-test.
a. If the RETRY icon is displayed then the instrument failed the self-test.
Press the UP button to return to the beginning of the SELF-TEST and
refer to the next section: Calibration Override.
7. Press the UP button. This will initiate the calibration sweep of the laser
wavelength. This takes about 45 seconds to complete and you will notice that
the gas concentration readings will go up and down.
8. When the OK icon is once again displayed, the instrument has passed the laser
calibration.
a. If the RETRY icon is displayed the instrument failed the calibration.
Press the UP button to return to the beginning of the self-test.
9. Press the UP button to acknowledge.
10. Press the SELECT button to scroll back to the run display.
What if the instrument failed the Self-Test and Calibration? Most often, the cause is due
to the transceiver not being properly positioned in the case or the laser wavelength has
drifted. Make sure the unit is in its proper position, all the way down, and flat. Note the
gas concentration. It is typically about 1100 ppm-m, but must be between 500 and 2,000
ppm-m. After rechecking the above, repeat the Self-Test and Calibration procedure
above.
Calibration Override
Should the unit fail at step 6 due to initial low readings perform the following actions:
1. Ensure the instrument is still in the Self-Test menu from step 6 above.
2. Override the normal Self-Test function by pressing the DMD button. This will
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