Vaisala GMT220 - Manual (Page 30)

USER'S GUIDE____________________________________________________________________
30 __________________________________________________________________ M010022EN-F
- Flow meter
- Field check adapter (Vaisala order code: 26150GM)
- Flexible tubing with 3 mm (1/8 inch) inner diameter
Two-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 back to the factory settings after the adjustment!
1.
Insert the probe into the field check adapter until the perforated
filter is covered.
0505-237
Figure 10 Field Check 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 low-end reference gas bottle. The side
port of the adapter is left open for gas outflow.
4. Let the low end reference gas flow and stabilize with a flow rate of
about 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 below). Press the button with a
small screwdriver. When pressing the button, the indicator turns to
adjusting mode.