Chapter 4 _________________________________________________________________ Operation
VAISALA ________________________________________________________________________ 89
CHEC Command
The CHEC command is used in the visibility calibration procedure to
display the two-minute average signal frequency in hertz. The
command has no parameters.
The display is terminated by pressing ESC. Pressing any other key
will pause the display. In the beginning, the eight-location buffer is
filled with the first value. The buffer is used to calculate the average
When the FDA13 calibrator is installed, the value displayed in the
message should be the same as printed on the calibrator glass plate. In
clear air the value should be near zero.
When you type
CHEC
↵
↵↵
↵
the output is the following:
SCALED FREQUENCY AVE (2 MIN)
999.9938
999.9880
>
FREQ Command
The FREQ command is for hardware monitoring. Message 4 gives the
same data line as the FREQ command.
An example of the output is the following:
>freq
OFFSET DIST SWID MAXI OWID
TE LEDI BACKS
VBB
TS
DRD
0.03
129.79 1.00
4
2
4
24.4
5.3
1303 19.5
23.1
900
0.03
129.79 1.00
4
2
4
24.4
5.3
1303 19.5
23.1
900
A new line is printed every 15 seconds. The command output is
terminated by pressing the ESC key. The first line is a title line with
the signal names.
DRY and WET Commands
The DRY and WET commands are used to check and adjust the
operation of the Rain Detector DRD12 analog signal measurement.