RKI Instruments M2A - Manual (Page 51)

M2A Transmitter Operator’s Manual 46
reading at the highest response and the M2A will continue to display this reading and retain it in its
memory until the fresh air adjustment procedure is completed. When calibration gas is applied to
the M2A during a zero adjustment, the M2A will freeze the display reading at the lowest response
to the calibration gas. The calibration gas can then be removed and the M2A will continue to
display this reading and retain it in its memory until the zero adjustment procedure is completed.
Adjusting the Fresh Air Setting
1. While in normal operation, press and hold the UP/YES button for 5 seconds to enter
Calibration Mode. Release the button when the following screen appears.
2. If you want to continue with calibration, press and release the UP/YES button to continue. The
display will indicate OXYGEN CAL Mode for a few seconds before showing FreshAir
Adjust?.
If you want to exit Calibration Mode, press and release the DOWN/NO button. The M2A will
indicate Leaving CAL Mode and the M2A will return to normal operation.
3. To continue with adjusting the fresh air (span) reading, press and release the UP/YES button.
ENTER will alternate with FreshAir on the top display line and the current oxygen reading
will be on the bottom display line.
To skip adjusting the fresh air reading, press and release the DOWN/NO button. The display
will indicate ZERO w/Cal Gas?. Skip to the next section, “Adjusting the Zero Setting”.
4. Screw the zero air cylinder into the fixed flow regulator.
5. Turn the regulator knob counterclockwise to open the regulator.
6. Allow zero air to flow for 2 minutes. If the oxygen concentration in the area is less than 20.9,
the reading should stabilize after 2 minutes.
7. Turn the regulator knob clockwise to close the regulator.
8. Unscrew the zero air cylinder from the fixed flow regulator leaving the calibration cup on the
detector. The M2A will continue to display the maximum gas response on the display and
retain the response level in its memory.
9. Press and release the ENTER button. The M2A will perform a fresh air adjustment and the
display will indicate ZERO w/Cal Gas?.
NOTE: If the fresh air adjustment fails, see “Troubleshooting” on page 39 for recommended
actions.
Adjusting the Zero Setting
1. If you want to continue with adjusting the zero setting, press and release the UP/YES button.
APPLY will alternate with ZERO Gas on the top display line and the current oxygen reading
will be on the bottom display line.
If you want to skip adjusting the zero reading, press and release the DOWN/NO button. The
display will indicate Leaving Cal Mode and the M2A will return to normal operation.
2. Screw the 100% nitrogen gas cylinder into the fixed flow regulator.
3. Turn the regulator knob counterclockwise to open the regulator.
4. Allow gas to flow for 2 minutes. The gas reading should be stable after 2 minutes.
Calib?
YES/NO