Hi,
I'm using the RP (stemLAB 125-10) as a DAQ system for acquiring data from pipe leak using an ultrasonic transducer. The RP is controlled via SCPI using a python script running on a laptop, ultimately the goal is to measure the RMS of a fixed number of samples. Right now the script acquires a buffer worth of data points at a decimation of 64 without a threshold.
I'm getting all sorts of strange behaviour in the acquired signals and I have absolutely no idea what is causing it. It's probably easiest for me to show you what I mean:
Exhibit A:
Exhibit B :
Exhibit C:
Exhibit D:
D shows what would be an 'expected' recording, I believe this was recorded using a pre amplifier. However, even with the pre amplifier more often than not the recordings would contain the strange behaviour seen in the other recordings. Notice in B at 8e-3 seconds the signal changes completely and shows what I would have expected to measure, it's much more similar to D.
Note: C was recorded without the leak running.
My first thought was that it was a grounding issue but from my research I couldn't see how to properly ground a RP. I'm not sure if its clear from the photos but the calibration is out of whack, I was planning on just applying an offset to the acquired signal rather than going through the rigamarole of doing it properly (I'm unfamiliar with the process and the calibration equipment).
I understand that the stemLAB 125-10 is a much older model so I plan on re-running the tests with a 125-14. I should mention I tested two different 125-10's to see if one of them was broken but got similar results on both, they were both shoved away in a cupboard so it may well be that they were both broken.
If anyone has any advice that would be really appreciated because I'm completely out of ideas now.
I'm a beginner at this sort of stuff so hopefully someone with a bit more experience could give me some support. Please let me know if there's any further information I can provide.
Cheers,
Jamie.
Strange DAQ measurements
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Re: Strange DAQ measurements
Hello Jamie,
Thank you for writing on the forum.
I am almost positive you also wrote to the Red Pitaya support email.
I have a couple of questions to provide more relevant feedback:
What are the requirements of the project? How fast do you need to capture data?
What Red Pitaya OS is installed on your Red Pitaya?
Here is a link to the example code, please try to use it as an example and build upon it:
https://redpitaya.readthedocs.io/en/lat ... l#examples
Thank you for writing on the forum.
I am almost positive you also wrote to the Red Pitaya support email.
I have a couple of questions to provide more relevant feedback:
What are the requirements of the project? How fast do you need to capture data?
What Red Pitaya OS is installed on your Red Pitaya?
Here is a link to the example code, please try to use it as an example and build upon it:
https://redpitaya.readthedocs.io/en/lat ... l#examples
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