Manual

A-1
Appendix A. SDI-12 Interface
If you are not familiar with the SDI-12 protocol, you can visit the following
web page and learn more about it:
http://www.sdi-12.org/sdi-12/table_of_contents.htm
A.1 SDI-12 Modes
The Vosponder is capable of emulating either an SDI-12 master unit or an
SDI-12 slave unit. The master mode is best used when the Vosponder is being
used with any SDI-12 compatible sensor or any SDI-12 device that cannot
issue SDI-12 extended commands. The slave mode allows the Vosponder to
be controlled by a datalogger, receiving data from the datalogger and then
verbalizing it upon command.
A.2 SDI-12 Slave Mode Commands
The Vosponder responds to a subset of the commands specified in the SDI-12
protocol. They are:
Command
Name
ASCII Codes Response Vosponder Action
Address Query ?! Address None
Acknowledge
Active
a! Address None
Send
Identification
aI! Address, ID
String
None
Change Address aAb! New Address None
Start
Measurement
aM! Address, 0011 None, SDI
Compliance Only
Retrieve Data aDx! Address, First
Data Location
of Last
Received Burst
None, SDI
Compliance Only
Verify aV! Address, 0011 None, SDI
Compliance Only
Send Data aXDnnnnnnnn
~!
Address Stores New Data
Speak Data Now aXS! Address Speaks Image w/Last
Data
Speak Alarm aXA! Address Speaks Alarm String
Speak Text aXTxxxxxxxx! Address Speaks Included Text
String
FIGURE A-1. SDI-12 Slave Mode Commands
Where a = the Vosponder SDI-12 Address, b = the New address, nnnnnn = the
input locations reporting, and xxxxxx = a text string.