3.9 Calibration

• For 30 C.F.R. Part 75 determinations (MSHA versions), the ALTAIR 4X Multigas Detector must be operated in the 0-5% by volume CH4 mode and must be calibrated with 2.5% by volume methane.

The ALTAIR 4X can be calibrated manually using this procedure or automatically using the Galaxy Test Stand. Refer to 7.7 of the Appendix. Calibration must be performed using a flow regulator with a flow rate set to 0.25 liters per minute.

If a battery charging cycle is interrupted before it is completed (4 hours for a fully discharged battery), allow the instrument’s internal temperature to stabilize for 30 minutes before performing a Calibration.

NOTE: The Galaxy Test Stand is not a CSA certified calibration method.

3.9.1 Fresh Air Setup and Zero Calibration

To skip the ZERO procedure and move directly to the calibration span procedure, push the ▲ button. If no button is pushed for 30 seconds, the instrument prompts user to perform a SPAN calibration before returning to the Normal Operation mode.

1. Press and hold the ▲ button in Normal Operation mode for three seconds.
2. If calibration lockout option is selected, enter password.

• ZERO screen displays.

If calibration lockout option is NOT selected:

• ZERO screen displays.

3. With the instrument exposed to fresh air, press the button to confirm the ZERO screen. A sensor Refresh and Zero Calibration now occur.

NOTE: Alternatively, press the ▼ button to execute a Fresh Air setup (FAS). See Section 3.2.2 for more details.

• After ZERO calibration completes, the instrument momentarily displays “ZERO PASS” or “ZERO ERR” along with the flag of any sensor that failed.

NOTE:

During instrument zero calibration, the oxygen sensor is also span calibrated to 20.8% oxygen fresh air, adjusting the calibration curve as needed. During instrument span calibration, the O2 sensor’s accuracy is checked against a known oxygen gas concentration without adjusting the calibration curve.

3.9.2 Span Calibration

To skip the Span procedure, push the ▲ button.

If no button is pushed for 30 seconds, the instrument returns to the Measuring mode.

1. Once the zero is set, the span screen displays.
2. Connect the appropriate calibration gas to the instrument.

3. Attach the calibration cap to the instrument.

• Insert tab on calibration cap into slot on instrument.
• Press calibration cap as shown until it seats onto instrument.

• Press both side tabs down onto instrument until they snap in.

• Ensure that the calibration cap is properly seated.
• Connect one end of the tubing to the calibration cap.
• Connect other end of tubing to the cylinder regulator (supplied in the calibration kit).

4. Open the valve on the regulator.
5. Press the button to calibrate (span) the instrument.

• LEDs flash
• SPAN calibration starts.

After the SPAN calibration completes, the instrument momentarily displays "SPAN PASS" successfully.

If a sensor is nearing its end of life, this"SPAN PASS" indication is followed by the end of sensor life warning (). The icon, and gas type of the sensor nearing end of life, blink for 15 seconds when the instrument returns to Measure mode. When in Measure mode, the heart icon is continuously displayed.

If the span calibration is unsuccessful:

• a Sensor Life Indicator displays (and ) to show the sensor has reached its end of life and should be replaced
• The unit remains in alarm state until the ▲ button is pressed
• The and symbols remain on the display until a successful calibration or the sensor in question is replaced.

NOTE:

A span calibration can fail for many reasons other than a sensor at the end of its life. If a span calibration failure occurs, verify items such as remaining gas in the calibration cylinder, gas expiration date, security of the calibration cap, etc. and repeat calibration prior to replacing the sensor.

3.9.3 Finishing Calibration

1. Close the valve on the regulator.
2. Remove the calibration cap.

The calibration procedure adjusts the span value for any sensor that passes the calibration test; sensors that fail calibration are left unchanged. Since residual gas may be present, the instrument may briefly go into an exposure alarm after the calibration sequence is completed.