Send data command (aD) - WXT530

WXT530 Series User Guide

Document code
English (United States)
Document type
User guide

Use this command to request the measured data from the device.

Start measurement command indicates the number of parameters available. The number of the parameters that can be included in a single message depends on the number of characters in the data fields. If not all the parameters are retrieved in a single response message, repeat the Send data commands until all the data is obtained.

Command format:

a Device address
D Send data command
x The order of consecutive Send data commands. Make sure the first Send data command is addressed with x=0. If all the parameters are not retrieved, send the next Send data command with x=1 and so on. The maximum value for x is 9.
! Command terminator


a+<data fields><cr><lf>
a Device address
<data fields> The measured parameters in selected units, separated with '+' marks (or - marks in case of negative parameter values).
<cr><lf> Response terminator
aD0 command can also be used to break the measurement in progress started with commands aM, aMC, aC, or aCC.
In SDI-12 v1.3 Continuous measurement mode (aXU,M=R) the sensor makes measurements at configurable update intervals. The aD command following the aM, aMC, aC, or aCC command always returns the latest updated data. Thus in aXU,M=R mode issuing consecutive aD commands can result in different data strings if the values are updated between the commands.