Campbell CS650, User Manual

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User Manual
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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. 10)
, 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,

2) Electrical Conductivity,

3) Temperature
m
3
/m
3
dS/m
°C
aM1!
1) Permittivity,

2) Electrical Conductivity,

3) Temperature
dS/m
°C
aM2!
1) Period,

2) Voltage Ratio,

3) Temperature

Sec
°C
aM3!
1) Volumetric Water Content,

2) Electrical Conductivity,

3) Temperature
4) Permittivity,

5) Period,

6) Voltage Ratio,

m
3
/m
3
dS/m
°C


Sec
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.
8.2.1 Use of Multiplexers
Multiplexers such as Campbell Scientific’s AM16/32B may be used to connect up
to 32 CS650 probes to a single control port. When using multiplexers, the
simplest configuration is for all probes to have the same SDI-12 address.
NOTE