program and the response time of the sensor, this may cause skipped scans to occur. In this case
make sure your scan interval is longer than the longest measurement time (ttt).
Table C-2: Example aM! sequence
0M!
The data logger makes a request to sensor 0 to start a measurement.
00352<CR><LF>
Sensor 0 immediately indicates that it will return two values within the
next 35 seconds.
0<CR><LF>
Within 35 seconds, sensor 0 indicates that it has completed the
measurement by sending a service request to the data logger.
0D0!
The data logger immediately issues the first D command to collect
data from the sensor.
0+.859+3.54<CR><LF>
The sensor immediately responds with the sensor address and the two
values.
C.1.7 Start concurrent measurement commands (aC!)
A concurrent measurement (aC!) command follows the same pattern as the aM! command with
the exception that it does not require the data logger to pause its operation, and other SDI-12
sensors may take measurements at the same time. The sensor will not issue a service request to
notify the data logger that the measurement is complete. The data logger will issue the aD0!
command during the next scan after the measurement time reported by the sensor has expired.
To use this command, the scan interval should be 10 seconds or less. The response to each
command has the form atttn<CR><LF>, where
a = the sensor address
ttt = time, in seconds, until the measurement data is available
nn = the number of values to be returned when one or more subsequent D commands are
issued.
See the following example. A data logger has three sensors wired into terminal C1. The sensors
are addresses X, Y, and Z. The data logger will issue the following commands and receive the
following responses:
ClimaVUE 50 Compact Digital Weather Sensor 44
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