Teledyne T200H User Manual page 259

Teledyne API - Model T200H/T200M Operation Manual
Note
07270D DCN7141
9. Set the HVPS coarse adjustment switch to the lowest setting that will give you just
above 3600 mV NORM PMT signal. The coarse adjustment typically increments
the NORM PMT signal in 100-300 mV steps.
Figure 7-17:
10. Adjust the HVPS fine adjustment such that the NORM PMT value is 3600-3700 mV.
The fine adjustment typically increments the NORM PMT value by about 30 mV.
It may be necessary to go back and forth between coarse and fine adjustments if the
proper value is at the threshold of the min/max coarse setting.
Do not overload the PMT by accidentally setting both adjustment switches to
their maximum setting. Start at the lowest setting and increment slowly. Wait
10 seconds between adjustments.
11. If the NORM PMT value set above is now between 3560-3640 mV, skip this step.
Otherwise, adjust the NORM PMT value with the gain potentiometer down to
3600±10 mV.
This is the final very-fine adjustment.
12. Note that during adjustments, the NORM PMT value may be fluctuating, as the
analyzer continues to switch between NO and NO
measure and AutoZero modes.
You may have to mentally average the values of NO and NO
adjustment.
13. Perform a software span calibration (Section 5.3, 7.4, or 7.6) to normalize the
sensor response to its new PMT sensitivity.
14. Review the slope and offset values, the slopes should be 1.000±0.300 and the
offset values should be 0.0±20 mV (-20 to +150 mV is allowed).
Pre-Amplifier Board Layout
Troubleshooting & Service
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response for this
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