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Hi,

I wish to record TDR waveform from TDR310h Acclima sensor, but I’m not very experienced in programming.
Has anyone written a program to get it?

Thanks in advance.

Rob

Hi,

Seems simple enough since it has an SDI-12 output. There are many sensors in the CS manuals that use the same protocol. Surely some other specific information on the commands can be found in its manual. There are many other information for the SDI-12 protocol and I leave you these 2 links. I can give you a support, I have used many SDI12 probes with CS loggers. In the meantime, give it a try.

https://www.sdi-12.org/current_specification/SDI-12_version-1_4-Jan-30-2021.pdf

https://s.campbellsci.com/documents/us/manuals/cs650.pdf

Smile

from Acclima web site:

The most convenient approach for capturing a waveform is to use the Acclima SDI-12 Reader.  A simple button push will cause the sensor to gather the waveform, compress it to save time in communicating it and then send it over the SDI12 cable at an elevated baud rate. The entire process takes about 6 seconds – most of which is communications time. The waveform can then be retrieved from the reader memory using its USB port.  The waveform points are stored in .csv format.

Retrieving a waveform without the Acclima SDI12 Reader can be done using the extended SDI-12 command:

        aXAtttt!

Where ‘a’ is the device address, ‘XA’ is the extended command code to report a point on the waveform, ‘ttt’ is a hexadecimal time ordinate in 5ps units and ‘!’ is the command terminator.  This command returns a hexadecimal string which represents the waveform amplitude time ordinate specified.

Example:  Request amplitude of waveform at time 1100 pico-seconds

1. Convert the time to 5ps units: 1100 / 5 = 220
2. Convert the 5ps time into hexadecimal: 220 => 0DC
3. Transmit the request (assumes address = 1): 1XA0DC!
4. Get the response string – for example: 18E6<CR><LF>
5. Strip off the address (1) and the terminator <CR><LF> = 8E6
6. Convert the code from Hexadecimal into decimal: 8E6 => 2278 amplitude units

The entire waveform can be downloaded by requesting successive points in time.  This process will take several minutes, and the sensor must be kept perfectly still throughout the process, as each point is measured at the time of the request.

Waveforms can be acquired more quickly using Acclima’s DataSnap products with the SnapView software, or by using the Acclima SDI-12 Sensor Reader.  These products dramatically speed up the download time by compressing data in using increased communication data rates that are not SDI-12 compliant.  Because of the high data rates, this type of waveform acquisition does not usually work well over long cables (greater than 10-20 meters).