MKS 649B - How to Adjust the Pressure Transducer Span; Table 9: Highest Pressure for Zero Adjustment of the Pressure Transducer

How To Adjust the Pressure Transducer Span Chapter Four: Operation
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1. Install the 649 controller in a system and connect a power supply/readout.
The pressure signal is available on pin 2 of the I/O connector. Use either pin 11 or 12 as the
ground. Refer to Table 7, page 18, for the pinout of the connector.
2. Pump the system down to a pressure below the resolution of the pressure transducer.
Table 9 lists the recommended pressure levels.
Highest Pressure for Zero Adjustment
of the Pressure Transducer
Full Scale Range Pressure
10 Torr [1.33 x 10
3
Pa] < 5 x 10
-4
Torr [6.66 x 10
-2
Pa]
100 Torr[1.33 x 10
4
Pa] < 5 x 10
-3
Torr [6.66 x 10
-1
Pa]
1000 Torr [1.33 x 10
5
Pa] < 5 x 10
-2
Torr [6.66 Pa]
Table 9: Highest Pressure for Zero Adjustment of the Pressure Transducer
3. Using a small screwdriver, adjust the
ZERO pot until the readout displays zero (0000).
Refer to Figure 6, page 21, for the location of the
ZERO pot.
How To Adjust the Pressure Transducer Span
Only adjust the SPAN pot in conjunction with a calibration transfer standard. Do not adjust the
span setting if a calibration transfer standard is not available. Instead, contact an MKS Service
Center for calibration.