Instruction manual

Appendix D. SDI-12 Sensor Support
D.1 SDI-12 Command Basics
SDI-12 commands have three components:
Sensor address (a) – a single character, and is the first character of the
command. The default address of zero (0) can be used unless multiple sensors
are connected to the same port.
Command body (e.g., M1) – an upper case letter (the “command”) followed by
alphanumeric qualifiers.
Command termination (!) – an exclamation mark.
An active sensor responds to each command. Responses have several standard
forms and terminate with <CR><LF> (carriage return – line feed). Standard
SDI-12 commands supported by the CS215 are listed in TABLE D-1.
TABLE D-1. SDI-12 Command and Response Set
Name Command Response
Acknowledge
Active
a! a<CR><LF>
Send
Identification
aI! allccccccccmmmmmmvvvxxx...xx<CR><LF>
Change
Address
aAb! b<CR><LF>
Address
Query
?! a<CR><LF>
Start
Measurement
aM! atttn<CR><LF>
Send Data aD0! a<values><CR><LF>
Start
verification
aV! atttn
D-1