Vaisala FD12P - Manual (Page 121)

Chapter 6 _______________________________________________________________Maintenance
VAISALA _______________________________________________________________________ 121
plates. In the correct position, the upper edges of the plates are
at the same level with the receiver and transmitter hood tips (see
Figure 31 on page 122). Tighten the clamp bolts.
NOTE Take a 30-cm ruler or equivalent and place it between the hood tips.
Then lift the glass plates until they touch the ruler. Tighten the clamp
bolts. Leave the calibrator clamp in place for the next calibrations.
Extra clamps can be purchased as optional items.
4. Move away from the optical path, and wait for 30 seconds.
5. Give the
CHEC
↵ ↵↵ ↵ command.
6. After two minutes read the displayed signal.
7. The signal value must be close to the one printed on the plates.
If the difference is less than 3 %, the calibration is correct. If
not, continue with the calibration procedure.
8. Terminate the CHEC command by pressing the ESC key.