OpenLog Artemis Frequency trouble

Development Boards Artemis
1

Hi,

I’m working with a an OpenLog Artemis (DEV-16832) with ADS122C04 ADC (Qwiic PT100) in Raw Voltage mode.

First without the ADS device attached, I’m able to set the logging frequency (in the “Configure Terminal Output” setting) to 240Hz and it records the IMU data with about 237Hz.

But with the ADS attached I can only set this to 89Hz and it actually loggs with just about 14Hz.

I’m curious where the limitations come from. Is the limit showing the Configure Terminal Output setting due to limits of the processor? If I’m not mistaken the ADS122 supports much higher frequencies. So is this something that could be solved by adding configuration options to the firmware? My goal would be to have a sampling rate of about 250Hz for IMU and ADS data.

In the future I’d like to attach an oximeter as well (I noticed that the firmware supports this now, which is great). This will probably have a lower sampling rate. Is it possible to mix a high sampling rate of the IMU und ADS data with the low frequency data from the oximeter, e.g. by only polling data every Nth time, or having separate log files?

Thank you for your help!

jonas

2

Hi Jonas,

I left a note to myself about exactly this in the OLA firmware:

https://github.com/sparkfun/OpenLog_Art … #L632-L636

So, I’m afraid what you’re trying to do is currently not possible. The OLA can log temperature from the ADS122 quickly, but not the raw voltage. It means upgrading both the OLA firmware and the ADS122 library.

Please raise this as a feature request issue in the OpenLog Artemis GitHub repo and I will look at it when I can (no promise of a quick fix - sorry!):

https://github.com/sparkfun/OpenLog_Artemis/issues

To answer your other question: no, sorry, it is not possible to mix and match the sample rates and/or use different log files for different sensors. The only solution at the moment is to use two OLA’s to log the data separately and to manually synchronize the logged data afterwards using the timestamps.

Very best wishes,

Paul