GasTech GTA-4100R Operator's Manual page 23

5. Refer to sensor specification sheet for correct sensor head voltage.
6. Carefully adjust P5 until the correct sensor voltage is reached.
NOTE: The adjustable voltage range is 1.4 -14.0 VDC.
7. Repeat this procedure for the bottom channel sensor voltage, by connecting a digital voltmeter
between TP9 (negative lead) and TP8 (positive lead). Then adjust P6 until the correct voltage is set.
8. Plug back in the top and bottom channel sensor input cables on the back plane.
9. Using a digital voltmeter, measure the head voltage at each sensor in the field. The voltage is
measured between the "Active" and the "Reference" conductors for that sensor. The difference from
the voltage at the card is the line drop in the cabling so this has to be adjusted for the system to
operate correctly.
10. Carefully re-adjust P5 (top channel) or P6 (bottom channel) for the correct voltage at sensor out in the
field.
11. Repeat this process for each sensor on each card.
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