MKS 907 Series, Инструкция по эксплуатации

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6 Service & Maintenance
29
Series 907 Analog Convection Transducer
Instruction Manual - #109070001
6.4 Troubleshooting
6.5 Calibrating for Zero and Atmosphere
The 907 Transducer calibration may change due to reasons such as filament contamination or aging
of the electronic components. If necessary, calibrate the Transducer. The two adjustments,
atmosphere and zero, can be made independently, but because of some interaction between them,
it is recommended to make the adjustments in the order below.
For best results, let the transducer remain at the calibration pressure for at least 15 minutes before
adjusting the potentiometers.
1. Connect a voltmeter to the output and common tip jacks (see Figure 5-1) or analog outputs (+)
and (-) on the D-sub connector.
2. With the transducer at a known pressure above 600 Torr, adjust the atmosphere potentiometer
(see Figure 6-1) for a voltmeter reading corresponding to the value in Figure 5-2.
3. With the transducer at any pressure below 10
-4
Torr, adjust the vacuum potentiometer for a
voltmeter reading of 0.375 V.
4. Repeat step 2. (This second adjustment of the atmosphere potentiometer will not cause more
than a few millivolts of error in the reading at vacuum.)
Table 6-1 General Symptoms/Possible Causes
Symptom Possible Causes Remedy
Pressure readings are
too low or too high
1. Contaminated sensor
2. Atm and Vacuum adjustments maybe
incorrectly calibrated
1. Test and replace if necessary (See
Section 6.9 and Section 6.10)
2. See Section 6.5
No analog output voltage 1. Power cable is disconnected
2. Power supply turned OFF
3. Defective PC board 1. Connect the power cable
2. Turn power ON
3. Return to MKS for repair
Analog output voltage
higher than 7 V
1. Analog output shorted to ground
2. Defective PC Board 1. Check the cable connections
2. Return to MKS for repair
Set point relay will not
operate
1. Set point voltage incorrectly set
2. Broken or shorted tube filament
3. Pin 7 of D-sub connector is
connected to ground at the power
supply (single set point model only.)
4. Defective PC Board
1. Check the set point
2. Test and replace if necessary (See
Section 6.10)
3. Check for any external switches
which may be controlling this line
4. Return to MKS for repair