MKS PDR-D-1, Инструкция по эксплуатации

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Fault Isolation Chapter Five: Maintenance and Troubleshooting
34
4. Isolate the power supply from the circuits in the PDR-D unit by disconnecting the power
supply jumpers. This will indicate a defective supply or some form of short or
malfunction in the PDR-D circuits.
If the power supply is defective, return the unit to MKS for further diagnostic testing. If
the power supply is functioning properly, continue with step 5.
5. Examine the pressure signal path through the system.
6. Use an external meter to measure the output of the pressure transducer (PRESS IN) at the
rear terminal block of the PDR-D unit. If this voltage closely (
±
0.2 V) tracks
1
the
voltage that is displayed on the front panel meter, but is still in error, the PDR-D unit is
functioning properly and the problem is in the pressure transducer or cable. If the
voltage does not track, proceed to step 7.
7. Troubleshoot the signal path in the PDR-D unit by disconnecting the pressure transducer
and replacing it with two resistors connected in the manner shown in Figure 8.
Pressure In
5.1k +5%
Ω
+15 V
S Gnd
10k +5%
Ω
Figure 8: Configuration of Two Resistors
This will produce an input voltage of 9.6 to 10.3 Volts. To produce a zero input, simply
short out the 10K resistor.
8. Use an external meter to measure the DC output voltage for this channel. Reference the
meter to S Gnd on the input connector. Refer to Figure 4, page 28. This voltage should
track the input voltage of step 7 to within
±
0.2 Volts. If it does not, the problem lies in
the channel amplifier and zero circuit. If the voltage does track but the digital meter does
not agree, either the meter or the overrange comparator is defective. Return the unit to
MKS for further troubleshooting.
1
A voltage above approximately
±
10.8 Volts will cause the digital panel meter to overrange and blank.
This is normal.