Bently Nevada 3300/70, Operation Manual

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114 I CALIBRATE CHANNELS (POT)
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CAUTION
84608-01
Valve Position Indication is not valid
until the calibration procedure has
been completed.
/r WARNING
High Voltage present
Could cause shock, bums
or death.
Do Not touch exposed
wires or terminals.
Calibration Procedure
(Note: the calibration figures refer to the test points and pots associated with Channel B,
calibration of Channel A uses the same procedure) :
1. With the transducer connected verify that the channel to be calibrated is OK (i.e., the OK LED
is ON).
2. Unscrew the front panel screws and slide the front panel over to obtain access t o the
Calibration Test Points and Calibration Potentiometers.
3. Note: Down scale corresponds to rotating the potentiometer (as viewed from the top) in a
counter clockwise direction such that the resistance measured between the "S" and "CW" terminals
increases. F o r both potentiometer full scale options, zero (valve fully closed) corresponds to the
resistance between the "S" and "CW" terminals being maximum (approximately 5 kohms).
4. Perform Zero Adjustment as follows: With the valve fully closed (maximum resistance between
the "S" and "CW" terminals) connect a voltmeter to the
ZB test point (TP20) referenced to the AC
test point (TP19). Adjust the ZB (Zero Channel B) potentiometer (R209) to 0.0 VDC +/- 5 mVdc.
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