Honeywell VA201T Calibration Handbook page 47

10. Ensure there is no gas present on the Certified Sensor.
If gas is suspected to be in the vicinity of the sensor either check the area using a calibrated portable
gas sensing device, e.g. Honeywell Analytic's Impact, or flow clean air over the Certified Sensor using
the Flow Housing accessory.
11. Press ok. The Transmitter Unit zeros the sensor. The LCD screen displays the message: Calibrating - Wait.
When successfully completed the LCD screen shows the message: Success! OK:Continue
12. Press ok. The Span Calibration screen is displayed with the message: Calibrate? OK/ESC. This gives
the choice to stop the calibration procedure at this point (after zero calibration) or continue to include the
span and full gas calibration.
13. Press ok to continue with Span Calibration. To skip the span calibration process, press the esc key.
WARNING
If Span Calibration is not required you MUST exit the process at this point otherwise the sensor will be damaged.
NOTE
!T THIS POINT DEPENDING ON THE TYPE OF GAS CARTRIDGE lTTED TO THE SENSOR A CHOICE OF TWO CALIBRATION GASES
may be displayed, e.g. C
FOR CALIBRATION AND PRESS OK /THERWISE THE PROCESS CONTINUES AT THE FOLLOWING STEP
14. Set the required test gas Span Conc. value using the up/down keys.
15. Press ok. The LCD screen displays the message: Apply Gas then <OK>
16. Connect the Flow Housing (using either gas pipe) to the regulated cylinder containing a known concentration
of the target gas at approximately the sensor alarm point, e.g. 50% LEL Methane in air.
It is recommended for most sticky gases the tubing should be PTFE with short pieces of rubber tube to
Apex Transmitter and Sensor
Zero Calibration
0
Calibrating - Wait
CO 100 ppm
Span Calibration
Calibrate?
H has the options C
7 8
Span Calibration
Span Conc.
Span Calibration
Apply Gas then <OK>
CO
Calibration Handbook
Zero Calibration
0
Success! OK : Continue
CO 100 ppm
OK/ESC
H and CH AS CHOICES )F SO CHOOSE THE ONE THAT WILL BE USED
7 8 4
50 %LEL
0
100 ppm
47