USB-6453 Dual Sampling Rate Acquisition

[sonofzakaria]

Hello,

I have a USB-6453 device and I want to perform data acquisition with two different sampling rates: one for voltage channels and another for thermocouple channels. How can I achieve this?

Thank you!

[GerdW]

Hi son,

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@sonofzakaria wrote:

I have a USB-6453 device and I want to perform data acquisition with two different sampling rates: one for voltage channels and another for thermocouple channels. How can I achieve this?

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Define two DAQmx tasks as needed and run them in parallel… (Your device allows for simultaneous sampling!)

What have you tried and where are you stuck?

[dsb@NI]

The USB-6453 specifications do not indicate multiple timing engines that would allow you to group channels to use different sample rates. I recommend using a single task at the higher sample rate. Decimate the temperature data to a rate that makes sense.

[LVNinja]

According to the specs, the USB-6453 has 8 individuals ADCs, there fore you can sample up to 8 different sample rates. 

Here you can find more information how to configure the channels https://www.ni.com/docs/en-US/bundle/veristand/page/daq-device-channel-properties.html?srsltid=AfmBO...

[dsb@NI]

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@LVNinja wrote:

According to the specs, the USB-6453 has 8 individuals ADCs, there fore you can sample up to 8 different sample rates. 

Here you can find more information how to configure the channels https://www.ni.com/docs/en-US/bundle/veristand/page/daq-device-channel-properties.html?srsltid=AfmBO...

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I think we may be confusing individual ADCs with timing engines. The 6453 has only one timing engine for the ai subsystem. If you try to configure and start multiple ai tasks, the first to start will reserve the timing engine, and the subsequent 2..N tasks will return error -50103 indicating "The specified resource is reserved." One can configure the task to acquire from multiple channels and each channel has a dedicated ADC. All the ADCs will use the same sample clock. 

[santo_13]

I agree with dsb@NI comments. You got only one timing engine and hence there can be only one HW timed DAQmx AI task running at a time.

Now, to your question, you can add both thermocouple and voltage channel to the same task with different types and capture at the higher sampling rate required and them decimate to get the lower rate.

Have you calculated the accuracy and resolution you get with the 6453 for your thermocouple and good with it, how about CJC?