Servomex DF-310E, Operator'S Manual

Page: 87 / 130

User Interface DF-310E 83
Figure 53: Span Check Menu
The GSF factor of the calibration gas can be entered directly or calculated by the instrument as
described on page 79. The legend (nGS) indicates the number of gases used to calculate the
GSF. If n has a value of zero, it indicates that the factor was directly entered, or the default value
of GSF=1.00 was used.
The Span Reference value SPAN REF is a numerical indicator for calibration changes made in
the field. All instruments are shipped from the factory with a SPAN REF value of 1000. The
number will decrease if the sensor's output decreases and vice versa. For example: For a 100
ppm Analyzer if a 70 ppm span gas is being used, the Analyzer reads 65 ppm, and an Oxygen
Cal is performed, the Span Reference will change to 928 ([65 ppm / 70 ppm] X 1000) following
the calibration process.
The following information should be recorded at each calibration:
Date
Span Gas Value
Old Span Ref Value
New Span Ref Value
Time spent sampling Span Gas
Note: If the sensor has lost or gained significant sensitivity, verify the quality of the gas used as
the calibration standard.
Review the section, Sampling Considerations During Calibration, on page 40 for information
regarding calibration standards, regulators, purging, and sample conditions. When introducing a
calibration gas into the sample system, it is important to maintain the same pressure and flow
conditions that occur during process monitoring.
NOTE
Over-pressurizing the Analyzer can result in permanent damage to
the sensor and optional pump. If the sample supply gas pressure
exceeds 10.0 psig, install a pressure regulator in the inlet calibration
gas line to regulate the pressure to 5.0 psig or less. The upstream
flow control valve is used to set the flow at 1.0 (scfh).
If the normal process sample is being supplied to the Analyzer under moderate vacuum
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