Calibration Handbook
148 XNX Universal Transmitter
Zero and Span Calibration for XNX
CAUTION
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.
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.
NOTE
Zero Calibration
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.
1. If using a compressed gas cylinder, push the calibration gas flow housing onto the bottom of the sensor
and apply the gas.
2. Access the Gas Calibration Menu.
NOTE
The Gas Calibration menu is for both Zero Calibration and Span Calibration.
Zero Calibration
Sensor Reading
at Current Settings
As the sensor detects the gas and the concentration increases, the values displayed will reflect the changing
concentration. When the concentration values are stable, 3 minutes, select
✓
to allow the transmitter to
calculate the zero adjustment. Selecting
✖
will return to the Gas Calibration menu.
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