Setra System Model 370 - Manual (Page 33)

Appendix II
CALIBRATION
The zero and span of the Model 370 Digital Pressure Gauge may be calibrated
using the following procedures. A high accuracy primary pressure standard is
recommended as the calibration source, since the high accuracy of the Model
370 will be adversely affected if the calibration pressure is not of equal or
greater accuracy.
The calibration procedure will require the same pressures, in the same
engineering units (usually PSI), as were originally calibrated at the factory.
During calibration, note that the gauge will display a prompt message, not the
actual pressure applied, and cannot be used to monitor the pressure input
during the calibration procedure.
II.1 ZERO CALIBRATION
1. Make certain the gauge is in a stable temperature environment for several
hours before calibration.
2. Press SETUP, then press ZERO. The display will read "APPLY" and the
pressure required for zero calibration.
3. Apply the indicated pressure from a high accuracy standard.
4. Press SETUP. The gauge will take data, adjust its zero calibration, and
return to normal display mode.
If the new zero data is too far from the factory calibration, the gauge will display
"UnAbLE". Verify the applied pressure. If it is correct, contact a Setra Applica-
tions Engineer for assistance.
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