Vaisala GMT220 - Manual (Page 32)

USER'S GUIDE____________________________________________________________________
32 __________________________________________________________________ M010022EN-F
16. Confirm the adjustment, press YES . By pressing NO you return
to adjustment mode display. (If the difference between the two
references is less than 20% of the measuring range of the probe,
adjustment cannot be done).
17. Adjustment is complete. Press BACK-EXIT to return to the basic
display.
18. Shut off the gas flow.
19. Replace the screw onto the adjusting button.
One-Point Adjustment Procedure
CAUTION Please take special care regarding the following when carrying out the
adjustment:
- Check that you give the correct reference concentrations in the correct
units.
- Check that the reading has really stabilized before accepting the
reading.
You cannot revert to the factory settings after the adjustment!
1. Insert the probe into the field check adapter (as deep as possible,
the perforated filter cover should be completely inside the adapter).
2. Connect the tubing to the bottom port of the adapter.
3. Connect the adapter with the tubing to the flow meter, the pressure
regulator and further to the reference gas bottle. The side port of
the adapter is left open for gas outflow.
4. Let the reference gas flow and stabilize with a flow rate of 0.6
l/min. Follow the reading of GM70, and after it has stabilized, wait
for 6 more minutes.
5. Take out the screw from the GM70 probe handle to expose the
adjustment button (see Figure 11 on page 31). Press the button with
a small screwdriver. When pressing the button, the indicator turns
to adjusting mode.
6. Press OK to confirm the adjusting.
7. Select CO2 , press SELECT.
8. Press YES to give the ambient pressure and temperature values.
To continue adjusting press EXIT .
9. Now the adjustment mode is on. Press GRAPH to see when the
readings have stabilized. Go back and press ADJUST to select the
adjustment method.