MKS 649A - How to Adjust the Pressure Transducer Span; Table 4: Highest Pressure for Zero Adjustment of the Pressure Transducer

How To Adjust the Pressure Transducer Span Cha
p
ter Four: O
p
eration
34
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 2, page 18, for the pinout of the connector.
2. Pump the system down to a pressure below the resolution of the pressure transducer.
Table 4 lists the recommended pressure levels.
Highest Pressure for Zero Adjustment
of the Pressure Transducer
Full Scale Range Pressure
10 Torr < 5 x 10
-4
Torr
100 Torr < 5 x 10
-3
Torr
1000 Torr < 5 x 10
-2
Torr
Table 4: 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.