USER'S GUIDE  ____________________________________________________________________ 
130  __________________________________________________________________ M211187EN-C 
3.  Stay away from the unit to avoid stray scattering into the receiver, 
and give command 
 
CALIBRATE VISIBILITY calibrator_value 
 
For example: 
 
CALIBRATE VISIBILITY 0.790   
NOTE 
Check the correct calibrator value from the opaque glass plates.
 
 
The calibrator value is printed on the labels of the glass plates. When 
command execution has finished, the FS11 responds DONE and 
calculates a new scaling factor and stores it in the non-volatile FLASH 
memory. 
4.  Leave the opaque glass plates in place and continue with section 
FSM102 Mechanical Alignment Check Procedure below to 
discover if the calibration check failed due to a mechanical 
misalignment. 
FSM102 Mechanical Alignment Check Procedure 
The mechanical alignment check procedure is performed as follows: 
1.  Perform the calibration check as instructed in section FSM102 
Calibration Check Procedure on page 128 (if not yet done). 
2.  Install the mask plates onto the calibrator plates by opening the 
thumbscrews holding the glass plates and sliding the mask plates 
under the thumbscrews as shown in Figure 42 on page 131. Secure 
the mask plates in place by tightening the thumbscrews. 
NOTE 
The mask plates are marked "RX" and "TX
," and they should face the 
receiver and transmitter,
 accordingly. 
 
NOTE 
The tape stripes on the mask plates should be placed against the glass 
plates to prevent the plates from scratching the glass plates.
 
 
3.  Move away from the optical path. 
4.  Give the CALIBRATE CHECK command. The command takes 
about 90 seconds to complete.