Solinst AquaVent SDI-12, User Manual

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SDI-12 User Guide for AquaVent
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5.4 Change Address Command: aAb!
This command is NOT supported by the Solinst AquaVent system (see Section 3.1).
5.5 Start Measurement Command: aM!
This command tells the AquaVent to take a measurement. However, the
measurement is not returned after this command. Instead, the time and
number of measurements that can be expected will be replied. For example:
0M! 00102<CR><LF> where the first “0” is the AquaVent address, the next
three digits “ 010 ” represent the time in seconds it will take the AquaVent to take
the readings, and the final “2” indicates how many readings will be returned.
The Solinst AquaVent will return a temperature and level measurement which
are always ready to be read after the specified time, after that the SDI-12 master
can issue the Send Data command 0D0! to retrieve the measurement data.
Other start measurement commands such as aM1 to aM9 are reserved for future
use.
5.6 Start Measurement Command with Checksum: aMC!
This command is identical to the aM! command with the exception that a three-
character checksum is returned before the <CR><LF> as part of the Send Data
command reply. The aMC1 to aMC9 commands are reserved for future use.
5.7 Send Data Command: aD0!
This command is used to get groups of data from the AquaVent. An aD0!
command is issued by the master after a M, MC, C, CC, or V command. The
AquaVent responds by sending the data. For a Solinst AquaVent, this is currently
two data items: temperature and level measurements. A typical command/reply
is:
0D0! 0+24.2981+0.35212<CR><LF> where the temperature is the
“+24.2981” in degrees Celsius and the level is the “+0.35212” in meters. It is
possible to change level units using Levelogger Software, but the actual units in
use are not reported while the AquaVent is in SDI-12 mode.
In response to a checksum request i.e. MC, CC; a typical command/reply
is:
0D0!
0+24.2981+0.35212MQ_<CR><LF> where the temperature and
level are as before and the final “MQ_” is the checksum. Refer to the SDI-
12 specification for details on the checksum generation. For the M and C
commands if a measurement cannot be obtained, the D command will return
0000<CR><LF> to indicate the measurement could not be obtained. The aD1
to aD9 commands are reserved for future use.
5.8 Start Concurrent Measurement Command: aC!
This command is similar to the Start Measurement Command except a concurrent
measurement is taken. Like the Start Measurement Command, a Send Data
Command is required to retrieve the data. For example: 0C! 000302 <CR><LF>.
The reply indicates that two readings (temperature and pressure) are available
after 3 seconds . A 0D0! command is then issued to read these AquaVent values.
The aC1 to aC9 commands are reserved for future use.
NOTE
Checksum is a form of redundant
test, which is used to check for any
errors in the data.
NOTE
The actual units in use are not
reported to the SDI-12 master while
the AquaVent is in SDI-12 mode,
but it is possible to change level
units using the Solinst Levelogger
PC Software (see Section 3.1)..