Campbell Scientific CS650 and CS655 Water Content Reflectometers - Manual (Page 48)

Appendix B. SDI-12 Sensor Support
Change Address Command (aAb!)
Sensor address is changed with command aAb!, where a is the current address
and b is the new address. For example, to change an address from 0 to 2, the
command is 0A2! The sensor responds with the new address b, which in this
case is 2.
Send Identification Command (aI!)
Sensor identifiers are requested by issuing command aI!. The reply is defined
by the sensor manufacturer, but usually includes the sensor address, SDI-12
version, manufacturer's name, and sensor model information. Serial number or
other sensor specific information may also be included.
An example of a response from the aI! command is:
313CampbellCS65X 000Std.00.35=2196405
where:
Address = 3
SDI-12 version =1.3
Manufacturer = Campbell
Sensor model = CS65X
OS version = 000Std.00.35
Sensor serial number = 2196405
Start Measurement Commands (aM! )
A measurement is initiated with M! commands. The response to each
command has the form atttnn, where
a = sensor address
ttt = time, in seconds, until measurement data are available
nn = the number of values to be returned when one or more subsequent D!
commands are issued.
Start Measurement Command (aMv!)
Qualifier v is a variable between 1 and 3 that requests variant data. Variants
include different subsets of the CS650 probe output:
M0! Volumetric Water Content (θ), Bulk Electrical Conductivity
(σ), Temperature (°C)
M1! Permittivity (ε), Bulk Electrical Conductivity (σ), Temperature (°C)
M2! Period (τ), Voltage Ratio (α), Temperature (°C)
M3! Volumetric Water Content (θ), Bulk Electrical Conductivity
(σ), Temperature (°C), Permittivity (ε), Period (τ), Voltage Ratio (α)
B-2