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Real time high speed data adquisition

Thu Jul 19, 2018 5:41 pm

Hello, I'm starting a new project where I want to build up a three-phase electric power analyzer, I want to use a Raspberry Pi for data adquisition (after the ADC) and transfer that data via ethernet to a remote PC. In this project I need to work with 9 separated channels and with a resolution of 12 bits(worst case scenario, around 6 or 8 bits) and sample at atleast 8 kHz.

I do not know very much about RPi, but I want to know if this is feasible, we own a Raspberry Pi 1 B+ in the company, but if needed we can get a RPi 3, thought we are limited in terms of possibility to import extra hardware for this project. Is it feasible with Python? Or would I have to use C and mess with the kernel?.

Thank you, Diego.

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Re: Real time high speed data adquisition

Fri Jul 20, 2018 5:09 pm

The pi can handle the data, especially if you write the low level loops in C (may not be needed), but I'm not sure how you plan to get the data into the raspberry pi.

i2c is probably not able to handle the data rate you need and even spi cannot quite make it.

The best library I know of for this type of thing is pigpio, and the web site has a example program for sampling using an mcp3008 at a maximum of 25KHz, but you need approx 75KHz.

Looks like this is going to be very challenging, and possibly not possible at all!

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Re: Real time high speed data adquisition

Fri Jul 20, 2018 5:30 pm

I suggest having a look at viewtopic.php?t=71089

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Re: Real time high speed data adquisition

Mon Jul 23, 2018 5:06 am

in my case I do it this way:
Raspberry PI- running as CODESYS plc - Ethercat - Beckhoff EK1100 - Beckhoff EL3403.

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