Chapter 5 ________________________________________________________________ Operation 
VAISALA ______________________________________________________________________ 163 
Start 
at Byte 
No. 
Content Description 
1 
! 
Start of the heading (ASCII 1). 
2 LT  LT31 sensor identifier. 
4 1  Unit identifier, if the ID is not defined it is 
replaced by a space character. 
5 
" 
Start of the text (ASCII 2). 
6 VIS 10000.0  MOR value, unit m, 1-min-average. 
   
18 AL 00000000000000000000  Alarm status of the LT31 system (see Table 13 
on page 164). 
42  BL 01000  Background luminance identifier and BL value, 
unit, cd m
-2
. 
51  AL 0  Alarm status of the background luminance 
sensor LM21. 
55 
# 
End of the text (ASCII 3). 
56 CSUM  Checksum CRC16. 
60 
$ 
End of the transmission (ASCII 4). 
61 
-* 
CR + LF (ASCII 13 + ASCII 10). 
 
The total amount of characters in the message is 62. The transmission 
times are: 2.1 s at 300 bps (10-bit char), 0.26 s at 2400 bps, 0.07 s at 
9600 bps.