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Chapter 7 __________________________________________________ Getting the Data Messages
VAISALA_______________________________________________________________________ 75
Example:
0I!
013VAISALA_WMT50103Y2630000<cr><lf>
Start Measurement Command (aM)
This command asks the device to make a measurement. The measured
data are not sent automatically and should be requested with a separate
Send data command
aD
.
The host device is not allowed to send any commands to other devices
on the bus until the measurement is completed. When several devices
are connected to the same bus and simultaneous measurements from the
different devices are needed, Start concurrent measurement
aC
or Start
concurrent measurement with CRC
aCC
should be used, see the next
sections.
See
Examples of aM, aC and aD Commands on page 79
.
Command format:
aMx!
The response is sent in two parts. The response part one:
atttn<cr><lf>
The response part two (indicates that the data is ready to be requested):
a<cr><lf>
where
a
=
Device address
M
=
Start measurement command
x
=
The desired sensor to make the measurement
1 = Wind
5 = Supervisor
If x is left out, the query refers to the combined data
message used for requesting data from several
sensors with just one command. See
Examples of
aM, aC and aD Commands on page 79
.
!
=
Command terminator
where
a
=
Device address