User manual

User Manual
5
Yellow Optional heater
power (see note)
12V 12V +12 SW Battery
Pink Optional heater
ground (see note)
G G G G
Grey Not used Not used Not used Not used
Unless special ordered, the heater will not be operational for
WXT520s purchased from Campbell Scientific. Although the heater
is not operational, the WXT520 will have a pink and yellow wire.
Do not connect the pink and yellow wire unless the heater is
operational.
6.5 Commands
Campbell Scientific uses the SDI-12 protocol to communicate with the WXT520.
Both "aM!" and "aR!" commands are supported (where "a" is the sensor address).
The preferred command is "aR!", since the communication is done in fewer steps.
The WXT520 is configured to run continuously so the output is identical.
Table 6-2 contains the outputs as configured by Campbell Scientific. All outputs
are in SI units.
Table 6-2. SDI-12 Commands
SDI-12
Command
Command
Function Values Returned
aR! or aM! Composite
Message
Wind Direction Average, Wind Speed Average,
Air Temperature, Relative Humidity,
Barometric Pressure, Rainfall Amount, Hail
Amount
aR1! or
aM1!
Wind Message Wind Direction Minimum, Wind Direction
Average, Wind Direction Maximum, Wind
Speed Minimum, Wind Speed Average, Wind
Speed Maximum
aR2! or
aM2!
PTU Message Air Temperature, Relative Humidity,
Barometric Pressure
aR3! or
aM3!
Precipitation
Message
Rainfall Amount, rainfall Duration, Rainfall
Intensity, Hail Amount, Hail Duration, Hail
Intensity
aR5! or
aM5!
Self Diagnostic
Message
Supply Voltage, Internal Reference Voltage
6.6 Programming
6.6.1 CRBasic
Dataloggers that use CRBasic include our CR200(X)-series, CR800, CR850,
CR1000, CR3000, and CR5000. These dataloggers use the SDI12Recorder()
instruction to read the WXT520.
The SDI12Recorder() instruction has the following form:
SDI12Recorder(Destination, Output String, Multiplier, Offset)
NOTE