Instruction manual

CS650 and CS655 Water Content Reflectometers
8.2 SDI-12 Measurements
The CS650 responds to SDI-12 commands M!, M1!, M2!, M3!, ?!, and I!.
TABLE 8-4 shows the values returned for each of these commands.
See Section 7.3, Datalogger Wiring
(p. 11), for SDI-12 wiring details.
This section briefly describes using the SDI-12 commands.
Additional SDI-12 information is available at Appendix D, SDI-
12 Sensor Support
(p. D-1), www.sdi-12.org, or
www.youtube.com/user/CampbellScientific
.
TABLE 8-4. CS650 SDI-12 Commands
SDI-12 command
(“a” is the sensor
address)
Values Returned
Units
aM!
1) Volumetric Water Content, θ
2) Electrical Conductivity, σ
3) Temperature
m
3
/m
3
dS/m
°C
aM1!
1) Permittivity, ε
2) Electrical Conductivity, σ
3) Temperature
dS/m
°C
aM2!
1) Period, τ
2) Voltage Ratio, α
3) Temperature
µSec
°C
aM3!
1) Volumetric Water Content, θ
2) Electrical Conductivity, σ
3) Temperature
4) Permittivity, ε
5) Period, τ
6) Voltage Ratio, α
m
3
/m
3
dS/m
°C
µSec
aM4! .. aM9!
No Values Returned
?!
Returns the SDI-12 Address
aI!
CampbellSci, OS version, Product
Serial Number
Up to 10 CS650 probes may be connected to the same datalogger control port
as long as each one has a unique SDI-12 address. The CS650 ships with a
default SDI-12 address of 0 unless otherwise specified at the time of ordering.
The SDI-12 address may be changed through DevConfig software (see Section
8.1, A200 and Device Configuration Utility
(p. 12)) or with a terminal emulator
in SDI-12 transparent mode (see Appendix D, SDI-12 Sensor Support
(p. D-1)).
SDI-12 communication is established using the SDI12Recorder() CRBasic
instruction. See Appendix D, SDI-12 Sensor Support
(p. D-1), for more detail on
SDI-12 communication.
NOTE
19