sampling across multiple channels

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sampling across multiple channels

Post by fred » Mon Dec 04, 2017 10:21 am

I have a question related to sampling across multiple channels, I haven't found anything about this topic.

The picolog 1216 is multiplexing the ADC across multiple channels.

I use streaming mode. I read that the fastest sample rate is 10 us per sample. If I enter for pl1000SetInverval a block of 1000000 us (1s), 10 channels and 1000 ideal number of samples across all channels (so 100 samples for each channel each 10 ms), how are the samples scheduled ?

Equally spread across all channels, or all channels as fast at possible and then wait for the next period

With equally spread, I mean e.g. for the first sample ch1 at 0 us, ch2 at 1000 us, ch3 at 2000 us, ch4 at 3000 us, ... and again ch1 at 10000 us
As fast as possible would be : ch1 at 0 us, ch2 at 10 us, ch3 at 20 us, ch4 at 30 us, ch5 at 40 us, ... and again ch1 at 10000 us

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Re: sampling across multiple channels

Post by Hitesh » Tue Dec 05, 2017 5:14 pm

Hi fred,

The channels are sampled sequentially. The ideal number of samples in the call to pl1000SetInterval() is the number of samples PER channel (there is an error in the Programmer's Guide which is being corrected).

If you ask for 1000 samples for each channel in 1000000 us, this should give an interval of 100 us between successive samples when you have 10 channels enabled.

Hope this helps,

Software Dev. Engineer

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