RKI Instruments 65-2660RK-01-04, Руководство оператора

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65-2660XL-XX-04 M2A-XL Transmitter Chapter 7: Maintenance • 41
Adjusting the Fresh Air Reading
Since there is a background of CO
2
in air of typically 300 - 600 ppm (0.03 - 0.06 %volume), it is
necessary to use a calibration kit with a 100% nitrogen cylinder to set the zero signal of an M2A-
XL with a low range detector (0 - 5000 ppm or 0 - 5.00% volume). Fresh air can be used to zero
an M2A-XL with a high range detector (0 - 50% volume or 0 - 100% volume).
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. The display
will indicate the target gas and 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-
XL will indicate
Leaving CAL Mode and the M2A-XL will return to normal operation.
3. To continue with adjusting the fresh air reading, press and release the UP/YES button.
ENTER will alternate with FreshAir on the top display line and the current gas 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
SPAN w/Cal Gas? . Skip to the next section, Adjusting the Span
Setting.
4. Screw the 100% N
2
cylinder into the fixed flow regulator.
5. Use the flexible tubing coming from the calibration adapter/splash guard to connect the
regulator to the calibration adapter.
6. Turn the regulator knob counterclockwise to open the regulator.
7. Allow gas to flow for the length of time determined in “Determining Response Time” on
page 39.
8. Turn the regulator knob clockwise to close the regulator.
9. Unscrew the cylinder from the fixed flow regulator. Leave the calibration adapter/splash
guard’s flexible tubing connected to the regulator. The M2A-XL will continue to display the
minimum gas response on the display and retain the response level in its memory.
10. Press and release the ENTER button. The M2A-XL will perform a fresh air adjustment and
the display will indicate SPAN w/Cal Gas? .
NOTE: If the fresh air adjustment fails, see “Troubleshooting” on page 36 for
recommended actions.
Calib?
YES/NO