SDI-12 Table Structure for sdit
#SDI-12
The table starts off as an indexed table with commands:
sdit = { {'1C5'}, {'2C1'}, {'2C2'}, {'3CC'} }
Once sdi12.go and sdi12.done have completed, there will be addition fields in the table structure.
| Table index | Type | Description |
|---|---|---|
sdit.c |
object | COM Port Object |
sdit[#].t |
number | Time in seconds, with ms resolution when ready. false if the device did not respond |
sdit[#].n |
integer | Number of samples (if a measurement command) |
sdit[#].v |
table | Table of results, or a string result. |
So, once sdi12.done returns true you can iterate through the table and locate the responses and values returned by the sensor.
Some sensors fail to cooperate on the bus.
For each measurement request in the table, the state machine asks the device to start - and the device responds with a time when it will be ready.
Between the request and the actual values, well behaved devices will ignore commands not intended for it.
Badly behaved devices will abort their measurement if you even talk to another device while it is measuring. 😱