Zero And Span Cal For Xnx With Mpd / 705 Comb / Sensepoint Comb; Zero Calibration - Honeywell VA201T Calibration Handbook

after the zeroing procedure. Do not allow the sensor to return to ambient air conditions.
WARNING
Long-term exposure (> 20 minutes) to concentrations exceediing the full-scale range of the sensor can cause it
to lose sensitivity. The ouput of the sensor may then decrease in value even though high levels of toxic gas are
still present. Before re-calibrating the transmitter, verify the absence of gas.

Zero and Span Cal for XNX with MPD / 705 Comb / Sensepoint Comb

CAUTION
Extended or frequent exposure to elevated concentrations of combustible gases may affect sensor sensitivity.
Verify sensor performance by frequent calibration.
Before initial calibration, allow the sensor to stabilize for 30 minutes after applying power. When in Zero and
Span Calibration modes, the current output from the sensor is inhibited (default 2mA) to avoid false alarms.
&OR MOST STICKY GASES EG (#L #L USE 04&% TUBING WITH SHORT PIECES OF RUBBER TUBE FOR THE lNAL CONNECTION DUE TO THE
INmEXIBILITY OF 04&%  4HIS MINIMIZES ADHESION OF THE GAS TO THE TUBE SURFACE AND ALLOWS MORE ACCURATE MEASUREMENT
To calibrate the sensor, use an appropriate span gas cylinder, tubing, magnet, and calibration gas flow housing.
Set the flow regulator to 300-375 ml/min for XNX EC sensors or 500 ±200 ml/ min for XNX mV sensors. A
compressed gas cylinder (20.9%Vol oxygen) should be used to perform the zero calibration if the area where
the sensor is located contains any residual amount of the target gas. If no residual gas is present, background
air can be used to perform the zero calibration. Contact a Honeywell Analytics representative for details about
suitable calibration kits.

Zero Calibration

The following equipment is required:
Flow housing (P/N: 1226A0411)
Test gas
Regulator
NOTE
Zero gas and Span gas should be at about the same humidity levels to avoid erroneous cell responses
This section outlines the steps for calibrating the transmitter's attached sensors.
NOTE
The Zero Calibration procedure should be performed prior to the Span Calibration procedure.
2. At the MPD, remove the weatherproof cap, if equipped.
3. Fit the flow housing onto the MPD.
4. Connect the flow housing (using either gas pipe) to the regulated cylinder containing zero gas.
5. Access the Gas Calibration Menu.
XNX Universal Transmitter
Calibration Handbook
151