Chapter Four: Operation
How To Adjust the Zero
31
Chapter Four: Operation
How To Adjust the Zero
All capacitance manometers require initial and periodic zero adjustments be made at a pressure
lower than their minimum resolution in order to ensure that the full dynamic range specified can
be achieved. Zeroing a transducer at some pressure above its stated minimum resolution will
create a “zero offset” relative (or unique) to the system on which the transducer is located. All
readings made subsequent to the offset will be linear and accurate relative to the offset zero value.
1.
Pump the system to a pressure below the resolution of the Type 122 transducer.
Refer to Table 6 for the recommended pressure values.
Suggested Pressure For Zero Adjustment
Full Scale Range (Torr)
Highest Base Pressure for Proper Zero Adjust (Torr)
10
1.0 x 10
-3
100
1.0 x 10
-2
1000
1.0 x 10
-1
5000
5.0 x 10
-1
10000
1.0 x 10
0
15000
1.5 x 10
0
20000
2.0 x 10
0
25000
2.5 x 10
0
Table 6: Suggested Pressure For Zero Adjustment
Note
The gauge should be in place and allowed to warm-up for at least 30
minutes before adjusting the zero.
2.
Set the ZERO potentiometer for an output of 0 Volts (display reads “0000”).
Refer to Figure 4, page 25, for the location of the ZERO potentiometer.
Note
Type 122 transducers are calibrated to specifications (refer to Appendix A:
Product Specifications, page 35) at the factory and every effort is made to
ensure that shipments arrive at your location free of defects or need for
further calibration other than zero adjustment. DO NOT attempt
adjustments other than zero.
Summary of Contents for Baratron 122B
Page 4: ...110899 P1 Rev D 8 98 MKS Baratron Type 122B Absolute Pressure Transducer ...
Page 9: ...List of Figures and Tables vi ...
Page 37: ...Sensor Chapter Three Overview 28 Figure 7 Cross Sectional View of the Type 122 Transducer ...
Page 43: ...Sensor Chapter Five Maintenance 34 This page intentionally left blank ...