Turning Red Pitaya into a multi-channel analyzer

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weardg
Posts: 10
Joined: Thu Dec 03, 2015 7:22 pm

Turning Red Pitaya into a multi-channel analyzer

Post by weardg » Mon Dec 07, 2015 2:24 pm

I recently acquired a Red Pitaya to be used to read in a 0-10V signal from a HIAC HRLD 150+ particle counter. This unit is being used to detect the presence of 4 to 70 micron particles suspended in hydraulic oil. Several ways to read the signal in already exist, one such method is using a multi-channel analyzer. This is one that is used with this particular sensor often:
http://www.amptek.com/products/mca-8000 ... lications/

The basic operation of a particle counter: a laser within the unit is passed through a column of fluid being precisely metered through the viewing area. This laser light then goes into a photo-diode and is converted into the analog signal. When a particle goes in front of the viewing area, a shadow is created, and a voltage pulse on the photo-diodes output is generated which is linearly proportional to the area of the shadow (particle size).

My hope for this project is to be able to read the signal in on the Red Pitaya over a period of time, say 1 minute, counting each pulse it sees as well as bucketizing the counts along with the peak voltage of the pulses into a histogram. (e.g., Pulses >= 30 mV and up >4 microns in size, pulses >= 60 mV and up >6 microns in size, pulses >= 100 mV and up >14 microns in size and so forth up the scale to 70 microns. At the end of the time period, the data (counts for each size bucket) would be sent to a data acquisition system which is recording other parameters for the test continuously (say temperature, pressure, flow rate etc...).

Any thoughts on how to attack this problem? I'm expecting to have to dive into some C programming if I needed to, but I also have MATLAB, so I didn't know if there was a clever way to do this using just the built in commands.

pavel
Posts: 520
Joined: Sat May 23, 2015 5:22 pm

Re: Turning Red Pitaya into a multi-channel analyzer

Post by pavel » Mon Dec 07, 2015 2:51 pm

I'm currently developing a multichannel analyzer application for Red Pitaya. The peak detection and histogram filling are running on the FPGA to reduce the dead time. The FPGA configuration and the part of the code running on the Red Pitaya board are more or less ready:
https://github.com/pavel-demin/red-pita ... ects/mcpha
The user interface is a work in progress.
Last edited by pavel on Fri Oct 14, 2016 12:42 pm, edited 1 time in total.

pavel
Posts: 520
Joined: Sat May 23, 2015 5:22 pm

Re: Turning Red Pitaya into a multi-channel analyzer

Post by pavel » Mon Dec 07, 2015 9:09 pm

Just added some notes about this project:
http://pavel-demin.github.io/red-pitaya-notes/mcpha/

It's still under development, so don't expect it to run out of the box.

I've tried to rebuild the FPGA configuration with Vivado 2015.4 and found some timing problems reported by this new Vivado version.

Stay tuned...

weardg
Posts: 10
Joined: Thu Dec 03, 2015 7:22 pm

Re: Turning Red Pitaya into a multi-channel analyzer

Post by weardg » Tue Dec 08, 2015 4:16 am

Wow! Looks pretty impressive so far! I'm trying to get up and running on this, and so far, I'm a bit overwhelmed.

One issue I'm facing now, is you state a PC running Ubuntu is required. I'm running this project at work, and currently all the PC's we have access to are Windows.

I might be able to get my hands on a spare PC and install Ubuntu on it, but curious as to what the reasons are that it must be a computer running Ubuntu? Is it just for the image building? Or for running the TCP server/control software?

Either way, I think I can eventually figure it out, and based on your screen shots, that is exactly what I am looking for! Thanks for the help!

pavel
Posts: 520
Joined: Sat May 23, 2015 5:22 pm

Re: Turning Red Pitaya into a multi-channel analyzer

Post by pavel » Tue Dec 08, 2015 10:33 am

weardg wrote: I might be able to get my hands on a spare PC and install Ubuntu on it, but curious as to what the reasons are that it must be a computer running Ubuntu? Is it just for the image building? Or for running the TCP server/control software?
It's currently easier for me to use Ubuntu and Debian distributions for the development.

The control software can run under Windows. Actually, it's how we run the version that works with our custom hardware.

What is needed is a Tcl 8.6 kit with the BLT library. I'll build this kit when I finish to debug all the components.

pavel
Posts: 520
Joined: Sat May 23, 2015 5:22 pm

Re: Turning Red Pitaya into a multi-channel analyzer

Post by pavel » Sat Jan 02, 2016 12:02 am

My multichannel analyzer starts to be usable. I've done some tests using the on-board DAC to generate Gaussian pulses:
Image

Here is how the resulting histogram looks like:
Image

Full width at half maximum (FWHM) is about 8-9 bins. I've noticed that with an Ethernet cable connected to the Red Pitaya board the noise is higher and FWHM is around 15-16 bins. Wi-Fi connection gives better results.

I've uploaded this multichannel analyzer application to the Red Pitaya Application marketplace:
http://bazaar.redpitaya.com/

This is an early version, so some bugs are to be expected.

smartengine01
Posts: 1
Joined: Tue May 31, 2016 11:13 am

Re: Turning Red Pitaya into a multi-channel analyzer

Post by smartengine01 » Tue May 31, 2016 11:17 am

Dear Pavel,

I am very intersted that you engage in making the control software more like that of Amptek, calculating centroid, loading cal files etc. If needed you can make some money of that, and I would be inretsted to buy. Please check admca_mca.zip (6 MB) in http://amptek.com/mca8000a-multichannel ... downloads/

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