Vaisala WMT700 - Manual (Page 179)

Chapter 5 _________________________________________________________________ Operation
WS425 A/B SDI-12 Message for V Command
When you have given the commands aV! and aD0!, the response
is the following:
a<watchdog><WS_unit><SDI-mode><spare><CR><LF>
where
a = Single-digit WMT700 address that corresponds to the
first character of the address value
<watchdog> = Number of times the watchdog has triggered. Ideally
should be zero. Format: +(c)c
<WS_unit> = Wind speed unit. The options are:
+0 = mph
+1 = kt
+2 = km/h
+3 = m/s
<SDI-mode> = Current sub mode setting. The options are:
+0 = SDI-12 sub mode A
+1 = SDI-12 sub mode B
<spare> = 1 digit for factory use, format: +c
<CR><LF> = Terminates the response
The above are verification data fields.
Requesting Cyclic Redundancy Check
Error detection capability can be enhanced by using the aCC! or
aMC! command to start the measurement. These commands have
the same function and send the same response as commands aC!
and aM! respectively. The difference is that Cyclic Redundancy
Check will be appended to the data returned by aD0! command.
The 16-bit Cyclic Redundancy Check value is appended to the
response of aD0! command before the <CR><LF>. It is encoded
as three ASCII characters using the following algorithm:
1st character=0x40 OR (CRC shifted right 12 bits)
2nd character=0x40 OR ((CRC shifted right 6 bits) AND
0x3F)
3rd character=0x40 OR (CRC AND 0x3F)
VAISALA _______________________________________________________________________ 177