7 SDI-12 Commands and Responses
The OTT PLS 500 communicates either using the physical SDI-12 interface or the RS-485 interface via the SDI-12 transfer
protocol. In this technical documentation, you will find a detailed description of the SDI-12 commands implemented in the
SDI-12 transfer protocol.
Further information on the SDI-12 standard can be found in the document "SDI-12; A Serial-Digital Interface Standard
for Microprocessor-Based Sensors; Version 1.4" (see website "www.sdi-12.org").
All advanced, manufacturer-specific SDI-12 commands on the OTT PLS 500 begin with "
X
". With these commands it is
possible to configure the OTT PLS 500, for example using the "SDI-12 trans parent mode" on a data logger or with the
OTT USB/SDI-12 adapter (accessory).
Conventions for measured value formats
p
– sign (+,–; if it is omitted from entries, the OTT PLS 500 automatically adds a "+")
b
– numbers (before the decimal point)
e
– numbers after the decimal point
7.1 Overview of SDI-12 commands
Standard commands
▶
a!
Confirmation active
▶
aI!
Send identification
▶
aAb!
Change sensor address
▶
?!
Query sensor address; factory setting:
0
▶
aV!
Carrying out a system test
▶
aM!
Start the measurement
▶
aM1!
Start measurement including statistical values
▶
aMC!
Start the measurement and request CRC
1)
▶
aMC1!
Start measurement including statistical values and request CRC
1)
▶
aC!
Start concurrent measurement
2)
▶
aC1!
Start concurrent measurement
2)
including statistical values
▶
aCC!
Start concurrent measurement
2)
and request CRC
1)
▶
aCC1!
Start concurrent measurement
2)
including statistical values and request CRC
1)
▶
aM2!
Query meta data of last measurement
▶
aMC2!
Query meta data of last measurement including CRC
1)
▶
aC2!
Query meta data of last measurement in concurrent mode
▶
aCC2!
Query meta data of last measurement including CRC
1)
in concurrent mode
▶
aR0!
Query data of continuous measurements
▶
aR1!
Query data of continuous measurements including statistical values
▶
aRC0!
Query data of continuous measurements including CRC
1)
▶
aRC1!
Query data of continuous measurements including statistical values and CRC
1)
▶
aR2!
Query meta data of last measurement for continuous measurements
▶
aRC2!
Query meta data of last measurement for continuous measurements including CRC
1)
▶
aHA!
Start "High Volume ASCII" measurement including statistical values and request CRC
1)
▶
aHB!
Start "High Volume Binary" measurement including statistical values and request CRC
1)
▶
aD0!
Send data after
aM!
;
aM1!
;
aM2!
;
aMC!
;
aMC1!
;
aMC2!
;
aC!
;
aC1!
;
aC2!
;
aCC!
;
aCC1!
;
aCC2!
;
aHA!
;
aV!
▶
aD1!
Send data after
aM1!
;
aM2!
;
aMC1!
;
aMC2!
;
aC1!
;
aC2!
;
aCC1!
;
aCC2!
;
aHA!
;
aV!
▶
aD2!
Send data after
aM1!
;
aM2!
;
aMC1!
;
aMC2!
;
aC1!
;
aC2!
;
aCC1!
;
aCC2!
;
aV!
▶
aDB0!
Send data after
aHB!
▶
aDB1!
Send data after
aHB!
1)
Cyclic Redundancy Check
2)
simultaneous measurement with multiple sensors on one single bus line
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