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Problem with SD card, sampling frequenzy

Posted: Mon Oct 16, 2017 10:54 am
by LFS
Hi!

We're trying to measure with strain gauges and are using an amplifier with an analog input to a RCP2. When setting logging frequency to 1000 Hz and looking into the logging file, we can see that it logs with an interval of 1ms. Everything good so far.

But the values are repeating and updating only every 20 ms which would mean that we are practically logging with a frequency of 50 Hz. We are using the the latest firmware and have tried to use earlier ones aswell. SD-card has been re-formated. Does anyone know what the issue could be?

Regards,
Rasmus

Posted: Thu Oct 19, 2017 3:19 pm
by brentp
Hi, when you are logging, can you see any flickering of the red LED on the front of the unit? This is an indication of the logger not being able to write to the SD card fast enough.

Also, What SD card do you have, and what is it's speed rating? Do you have any other cards that are faster?

Thank you,

Posted: Sun Oct 29, 2017 9:41 am
by LFS
Hi,

Thank you for your response! Yea, the red light isnĀ“t flickering.

Regarding the SD card we are using Kingston 8 GB SDHC, with a speed class 10 and UHS-I speed class 1. Do you have any sensors that you recommend using with the RCP2?

Regards,
Rasmus

Posted: Mon Oct 30, 2017 4:34 pm
by brentp
Hi, this is a confirmed issue. We're working to have the fix available in the next firmware; ETA is next couple of weeks.

We have sensors we like available in our online store, but RCP can work with any 0-5v source.
https://www.autosportlabs.com/product-category/sensors/

Thanks,

Posted: Mon Oct 30, 2017 8:08 pm
by LFS
Okey thank you for quick and good respons, good to know what the issue is! So what is the maximum frequency at the moment?

It was to suppose to say SD-cards, not sensors, sorry :)

Regards,
Rasmus

Posted: Mon Oct 30, 2017 8:21 pm
by brentp
50Hz.

Any high quality name brand card 32GB or less should work.