Vaisala WS425 - Manual (Page 58)

USER'S GUIDE____________________________________________________________________
58 __________________________________________________________________ M210361EN-E
Start Measurement Command (aM!)
With this command, the sensor will make a measurement. The sensor
will not return the measurement to the data recorder after this command.
It shows the time after which the measurement result can be retrieved
using the D0! command and it also shows the number of parameters. The
following is an example:
>0M!
00015
The SEND DATA (D0!) command must be issued to get the
measurements.
The command is the following:
aM!
where
a = The sensor address.
M = The start measurement.
! = Terminates the command.
The response is the following:
atttn<CR><LF>
where
a = The sensor address.
ttt = The specified time, in seconds, until the sensor will
have the measurement ready (001).
n = The number of measurement values the sensor will
make and return in one or more subsequent D
commands (5).
<CR><LF> = Terminates the response.
Send Data Command (aD0!)
This command is used to get instant data from the sensor. D0! must be
preceded with an M! command or an V! command. The sensor responds
by sending measurement data (after M!) or verification data (after V!).
In a SDI-12 system compliant with the standard, if the expected number
of measurements is not returned in response to a D0! command, a data
recorder issues D1!, D2!, and so on until all measurement values are