Vaisala WXT520 - Manual (Page 82)

User’s Guide ______________________________________________________________________
80 __________________________________________________________________ M210906EN-C
Example (the parameters included can be chosen from the full
parameter set of the commands aR1, aR2, aR3 and aR5):
0R0,Dx=005D,Sx=2.8M,Ta=23.0C,Ua=30.0P,Pa=1028.2H,
Hd=0.00M,Rd=10s,Th=23.6C<cr><lf>
For selecting the parameter set in the response message, see Chapter 8,
Sensor and Data Message Settings, on page 107 .
Automatic composite data messaging is a concurrent, not an alternate
mode to either the polled or automatic modes.
SDI-12 Protocol
There are two different modes available for providing all the
functionality of the SDI-12 v1.3 standard.
The lowest power consumption is achieved with the Native SDI-12
mode (aXU,M=S), as it makes measurements and outputs data only
when requested. In this mode all the commands presented in this
chapter are available except those for the Continuous measurement.
In the Continuous mode (aXU,M=R) measurements are made at user-
configurable update intervals, see
Chapter 8, Sensor and Data Message
Settings, on page 107 . The data is outputted on request. In this mode all
the commands presented in this chapter are available.
For changing the message parameters, units and other settings, see
Chapter 8, Sensor and Data Message Settings, on page 107 .
In the Native SDI-12 mode (aXU,M=S) the WXT520 is in idle state
most of the time (power consumption < 1 mW). More power is
consumed only during the measurements and data transmit requested by
the host device. Especially, the wind measurement typically consumes
60 mW average power (with 4 Hz sampling rate), throughout the
averaging period. In the Continuous mode (aXU=M,R) the power
consumption is determined by the internal update intervals of the
sensors and wind averaging time. These have certain limits, so very
long measurement intervals can not be achieved with this mode. Also
the power consumption between the measurements is about three times
that of the Native mode.