DigiVac 200P/2c Руководство по эксплуатации - Страница 6
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5.0
TROUBLESHOOTING
If the gauge reads 760 torr and does not respond to vacuum, it is likely that the
thermocouple voltage is not getting to the gauge. The cause could be:
Bad thermocouple
Bad cable connection On Model 200P, check cable wires at terminal strip
If the gauge reads 0:
Bad thermocouple
Bad cable connections See above
6.0
RECALIBRATION
If the tube is replaced, the unit must be recalibrated. It is best if this is performed at
Digivac. If field calibration is done, the zero and span adjustments are available on two
potentiometers which are accessible by removing the front panel of the instrument. The
zero is on the right and the span is on the left. Make slight adjustments and wait a few
seconds for the effects of the adjustments to be seen. On the 801 series gauges, the zero
adjustment is located on the front panel.
Atmosphere
▪ Energize the unit at atmospheric pressure. Remove the front panel.
▪ Make sure that the gauge tube is in a vertical orientation, because it is position sensitive.
▪ Connect a Voltmeter to the two pads available from the right side of the printed circuit
board, these are called Zero and Atm .420
▪ Adjust the potentiometer labeled "Atm" (leftmost) until the voltage above equals .420
▪ This gives an approximate adjustment. Now expose the tube to a pressure of 600
millimeters of mercury and adjust for 600 on the display.
Zero
Operate the unit at the lowest attainable pressure.
▪ 1 Micron with a diffusion pump,
▪ 10 to 15 Microns from a belt-driven two-stage mechanical pump,
▪ 35 Microns from a direct-drive, two-stage mechanical pump,
▪ 500 Microns from a single-stage mechanical pump,
Replace gauge tube
On Model 200, check red, black, green and white wires on 9 pin
dsub connector
On all units, check soldered connections
On octal connector
Replace gauge tube
Model 200 with
cover removed
Atmos Adj.
Zero
Adj.
6