Vaisala WS425FG - Manual (Page 45)

Chapter 4 ________________________________________________________________ Operation
VAISALA_______________________________________________________________________ 43
Notes:
1. Bytes 28-29 are the modulo 256 hexadecimal checksum of the
ASCII values calculated for bytes 2 through 27.
2. Sensor response message status byte in all applicable messages
reporting a sensor status, the status byte (byte 4) indicates the
following: P (Pass) indicates that all diagnostic tests have passed
and the sensor is functioning normally. F (Fail) indicates that one
or more of the diagnostic tests have failed. The user can then
request diagnostics and extended tests (WD) to further isolate the
problem. H (Heater failure) indicates that the wind reading is valid
but one or more built-in heater diagnostic tests have failed.
3. When the status byte is F, the wind direction fields are set to 999
and the wind speed fields are set to 999.9 in the applicable sensor
response messages. This does not apply to the WF command
response.
WL Command
This command sets the heater function to be automatically controlled by
the sensor. The command format is:
WL CR LF
The sensor response to the WL command indicates the status of heater
control after execution. In this mode the sensor automatically controls
the operation of the transducer heaters, based on an internal sensor
algorithm.
The response to this command is the following:
Heaters on automatic control CR LF
26-27 Signal quality 99
28-29 Hex checksum (note a) xx
30 End of text ETX
31 Carriage return CR
32 Line feed LF
Table 4 Explanation of the WA Command Message
Byte Description Value