Vaisala GM70 - Manual (Page 50)

USER'S GUIDE ______________________________________________________
50 _____________________________________________________ M010139EN-G
1. Insert the probe into the field check adapter until the perforated
filter is covered.
0505-237
Figure 17 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 16 on page 48). 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 confirm that the
readings have stabilized. Go back and press ADJUST to select the
adjustment method.
10. Select 2-point adjustment , press SELECT . Press READY with the
stabilized reading in the lower reference concentration.
11. Give the lower reference concentration value by using the arrow
buttons (for example, if you are using pure nitrogen, enter value 0
ppm). Take care that you give the correct value in correct units, as
you cannot revert the earlier values after accepting the new values.
Press
OK .
Next move on to the adjustment at the second (high-end)
reference point.
12. Take out the tubing from the low-end gas bottle and connect it to
the high-end gas bottle.