user manual

Input Calibration
January 2009 UDA2182 Universal Dual Analyzer Product Manual 171
Calibrating the Integral Pressure Sensor
Introduction
The concentration of oxygen dissolved in air-saturated water depends on the barometric
pressure. This dependence is automatically compensated for during air calibration using a
pressure sensor built into the Analyzer. The purpose of the pressure calibration is to
calibrate that pressure sensor. However, this sensor has been factory calibrated and should
not require re-calibration.
Procedure
Determine the true ambient barometric pressure, such as from a calibrated pressure
transmitter or a mercury barometer. Absolute barometric pressure is required - not the
“relative” sea-level pressure normally reported by the weather bureau.
Table 8-13 Calibrating the Integral Pressure Sensor
Step Action Screen
1
Press
Calibrate
CALIBRATION
Input Temp Cal
Output Cal
Cal History
Input PV Cal
CALIBRATION
Input Temp Cal
Output Cal
Cal History
Input PV Cal
2
Press
Enter
PV INPUT CAL
In 1 DO Cal
PV INPUT CAL
In 1 DO Cal
Use
to select
Input 1 or 2 DO Cal
3
Press
Enter
IN1 DO CAL
Sample Cal
Air Cal
Pressure Cal
Bias Volts
Reset Cal Factor
Reset Bias Volts
Bias Scan
Pressure Offset
Reset Prs Offset
IN1 DO CAL
Sample Cal
Air Cal
Pressure Cal
Bias Volts
Reset Cal Factor
Reset Bias Volts
Bias Scan
Pressure Offset
Reset Prs Offset
Use
to select
Pressure Cal