Manual

User manual/ Technical information
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SDI-12
SDI-12 communication adopts three wires, two of which are sensor power supply wires and the other is
SDI-12 signal wire.
Each sensor on the SDI-12 bus has a unique address, which can be set to ‘0’, ‘1’ ~ ‘9’, ‘A’ ~ ‘Z’, ‘A’ ~ ‘Z’.
The SDI-12 address of the SenseCAP ONE defaults to ‘0’. The instructions supported by this sensor are
shown in the next chapter, where each instruction conforms to the SDI-12 v1.4.
The sensor is powered by a DC power supply of 3.6~16V. After the sensor is powered on, it will go into
sleep mode immediately and wait for the data acquisition equipment to give instructions. SDI-12 uses baud
rate 9600bps, 1 start bit (high level), 7 data bits (high 0 and low 1, anti-logic), 1 even parity bit, and 1 stop
bit.
The sequence of each byte sent is shown in the following figure:
4.3.1 SDI-12 command and response
Command format
 Start with device address ‘a’, it is ‘0’in the following sample.
 End with ‘!’as a terminator
 The response command end with the <CR><LF>
Query the device
address
?!
Send ?!
Response 0<CR><LF>
Description The sensor at address '0' responded to the query
Query the device
status
0!
Send 0!
Response 0<CR><LF>
Description Address '0' of device online
Query the device
information
0I!
Send 0I!