Download 7400 Plus - User Manual

7400 Plus
Instruction Manual
3.7.1. Determining Span Gas to Use
Typical calibrations are performed using methane gas as the Span Gas. For accurate readings of
other types of gas, the Span Gas must match the gas to be measured. However, to calibrate a
sensor for detection of other gases, a surrogate gas, propane, can be used. Appendix B details how
to apply a K-factor to the propane surrogate gas to obtain detection of other gas types.
3.7.2. Sensor Calibration Procedure
To perform a calibration from the 7200 Plus, perform the following:
NOTE
CAL MODE AUTOMATICALLY EXITS IF NO KEYS ARE ACTIVATED AFTER 5 MINUTES.
1) To enter Cal Mode from any data display, press the DOWN / CAL key then use the
UP/DOWN keys to select the channel to calibrate.
2) Apply Zero gas to the sensor to be calibrated with an appropriate Zero calibration standard.
Wait approximately five minutes or until readings are stable at the LCD display, then press
the EDIT key to perform the Zero calibration.
3) If the Zero calibration is successful, Cal Mode automatically proceeds to the Span check.
4) Apply Span gas to the sensor to be calibrated that matches the selected value set in the Cal
Setup Menu. Wait approximately five minutes or until readings are stable at the LCD display,
then press the EDIT key to perform the Span calibration.
NOTE
REFER TO PARAGRAPH 4.3.3 FOR INFORMATION ON SETTING OR VERIFYING THE SPAN GAS VALUE.
5) If the Span calibration is successful, the display flashes REMOVE CAL GAS and starts the
Cal Delay.
6) CAL MODE will be complete after the end of the CAL DELAY.
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