CS120A and CS125 Visibility and Present Weather Sensors
58
This should be carried out every two years to check for any slight drift in the
dirty window detection.
To carry out the dirty window zero offset calibration make sure the windows
are very clean. Temperature should ideally be in the range 15-30°C and the
sensor should have been powered up for over 5 minutes.
CS125 CALIBRATION - MENU 3
ID 0
S/N 1006
(1) Perform calibration
(2) Restore the factory calibration
(3) Perform dirty windows zero offset calibration
(4) Restore dirty windows factory calibration
(9) Refresh
(0) Return to main menu
Typing ‘3’ returns text similar to the following:
Current values EO=3200 DO=4649 DD=995
Cal DW offset? Y/N?
Then type ‘Y’. The sensor responds in a similar way to the following:
Calibrating dirty window system...Please wait
DD=990 DO=4535
DD=1000 DO=4531
DD=1010 DO=4373
DD=1020 DO=4206
DD=1030 DO=3886
DD=1110 DO=2675
DD=1120 DO=2682
DD=1130 DO=2530
DD=1140 DO=2392
EO=3230 ES=371 DO=2251 DS=234 DD=1140
Press any key to exit (Not return)
Press any key and the dirty window zero offset calibration is complete.
16.3 Internal temperature check (CS125 only)
The CS125 has an internal temperature sensor in one of the cross arms. This is
used as part of the present weather identification if a CS215 temperature and
RH sensor is not connected. This does not need recalibration but can be
checked if a suitable nearby reference temperature measurement is available.
The CS125 external temperature given in some standard messages (see
Message Formats: A breakdown of the different default outputs of
the sensor – Basic/Partial/Full
(p. 24)
) or in the system information menu (see
Entering the sensor menu system
(p. 49)
) should be within about 3°C
of the reference. The comparison should ideally be made in cloudy and windy
conditions and as near to 0°C as possible.
