Calibrating a Remote CXT2 Mounted at the Ceiling

Procedure to Perform ZERO and SPAN Calibrations

1. Enter Calibration mode from any of the Data Display Screens by swiping the Down/Cal key and then swipe the Edit key to enter Cal Mode.
2. Apply a clean Zero Gas using the Calibration Cup or be sure there is no background target gas in the monitored area. After the reading is stable, swipe the Edit key to set the Zero Calibration. To skip the Zero calibration, and go to the Span calibration, swipe the Next key. Once a message that the Zero calibration was completed successfully has been displayed, proceed to the next step.
3. Apply the correct, as indicated, span gas. After the reading is stable, swipe the Edit key to set the Span Calibration. To skip the Span Calibration, swipe the Next key. When a message that the Span Calibration was completed successfully is displayed, the gas detector will exit back to the Data Display Screen.
4. Remove the calibration gas. Once the Cal Purge Delay has expired, normal alarm and relay functionality will be restored.

WARNING: The SPAN gas used must match the Cal Span Value specified in the CXT. The Cal Span Value may be edited if it becomes necessary to apply a different SPAN gas concentration.

7. When tubing is clear of residual span gas, attach a filter fitting to the end that was attached to the gas cylinder to protect it from clogging or damage and coil or roll it up securely out of the way.

Diagram Descriptions:

A remote CXT2 sensor is installed on or near the ceiling with 6.35 mm (¼ in) tubing attached (Teflon is recommended).

A permanently installed length of calibration tubing is attached to the calibration adapter on the remote CXT2 sensor. The other end can be easily attached to a cylinder of gas during the calibration process.

The calibration adapter is screwed onto the end of the remote sensor.

The standoffs create space for the gas to pass over the sensor.

The calibration tubing is attached to the nozzle.

A remote sensor can be mounted up to 4,000 ft or 1,219 m away from the CXT2 transmitter.

Calibration is performed at the main CXT2 which is mounted at eye level.

*When finished calibration, detach the tubing from the gas cylinder. If allowing diffusion to clear the tubing, the CXT2 may not return to a zero reading for several minutes. If using zero air with a 0.5 LPM regulator, expect 5 seconds per 10 meter length before the CXT2 returns to a zero reading. When the reading reaches zero stop the air flow.