Saleae - Logic 2

Looking for much lower sample rates

I want to use our Salae to monitor battery charge/discharge cycles that take places over hours and at times days. The Salae is ideal for this kind of test since I can monitor the battery voltage (analog), temperature (analog voltage at the thermistor), battery undervoltage protection status (digital), battery full detection (digital), current draw (analog voltage on sense resistor using an amplifier like uCurrent), etc etc.

I find that the lowest limit of 625 samples/sec is too fast for our application we need something more like 1 sample/sec so we don’t run out of memory over the test period.

Do you get many requests for this? It seems like a fairly common scenario. Thanks.

Great use case! We have support for analog sampling down to 10 S/s on our Gen2 products.
Screen Shot 2019-12-11 at 6.45.53 PM

Hey Tim,

Yes I can get the analog sample down to 10S/s but the digital sample rate is still very high (100MS/s) so I still capture a lot of data for long periods of time with the mixed signal scenario. I guess the trick would be to capture everything as Analog, should have thought of this.

Which channels do you have active?

For this example I’m just using 0 for Analog and 1 for Digital.

What Saleae product are you using?

It’s a Saleae Logic 8 device ID is 2454AA*********. Not sure is that is gen2, it’s fairly new (~12months).

Are you running on our latest 1.2.x software? Link below.

Yes, I’m using 1.2.18 on Linux, I also tried the 2.x beta.

In general it seems like 10S/s will be ok if we capture everything as Analog, 1S/s would be nice but not critical. I understand why you would not offer low sample rates for Digital, it can be confusing when information is lost between samples.

Thanks,
Tom

Thanks for those details. I have 2 notes below.

  1. Sampling at a higher digital sampling rate does consume more USB bandwidth. Though, as long as the number of transitions in the capture stays the same, the file size for your final capture will stay the same. Memory is only consumed when transitions in the data occur. So, unless you are experiencing USB bandwidth issues, I would continue sampling at the highest digital sampling rate while sampling analog at 10S/s.

  2. When combining digital and analog channels in a single recording, you can decrease the total sampling rate as per the image below:
    Screen Shot 2019-12-12 at 4.13.23 PM

Hope that helps!