Precipitation Sums - Vaisala PWD22 User Manual

User's Guide _______________________________________________________________________
NOTE

Precipitation Sums

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The ID has a two-character field because it can be two characters long.
An example of the polled (and automatic) message 0 format is the
following:
PW 1 00 500
PWD22 waits about 100 ms before it transmits the polled message to
give the host time to turn the RS-485 line into the receive mode.
For compatibility in the system level, PWD22 also accepts FD
instead of PW in the polling commands because the data message
formats and framing are the same as in the VAISALA FD12 and
FD12P sensors. If PWD22 is polled by
start with FD 1 ..
PWD22 has no internal clock for automatic resetting of the sum data
at certain times. This can be done by the host with the following
command:
PW id C
where
= ESC (ASCII character 1B hex).
C
= Carriage Return (13 hex.)
R
PWD22 then responds to the accepted command with the ASCII
character < (06 hex).
The host computer can also maintain its own sum calculated from the
continuous PWD22 data. This may be safer, if the PWD22 power
breaks often and resets the sums before the scheduled time. The water
sum is automatically reset, when it reaches 99.99 mm and the snow
sum at 999 mm.
700
FD 1 2 , the answer will