Multi-channel logging with different triggers and looped 3-minute data acquisition cycles

[wndulwlsp]

Hi everyone,

I’m a beginner in LabVIEW and currently working on a project involving concrete mix testing. We're using a DAQ to acquire analog signals from two devices: a non-contact ultrasonic sensor and a Pundit tester.

Here’s what I want to do:

• Each time we acquire 2000 samples, that’s one complete signal.

• We repeat this process 100 times, ending up with a matrix of 2000 rows × 100 columns (each column = one signal).

• I want to average these 100 signals row-wise, resulting in a single signal of 2000 averaged points.

  • This is similar to how the Average function in Signal Express works.

• Then, this whole process (acquire + average) should repeat every 3 minutes.

  • For example, if the first acquisition starts at 12:05, the next cycle should start at 12:08, regardless of how fast the averaging finishes.

I’ve attached a vi file I'm working with for clarity.
Since I’m new to LabVIEW, I’m having a hard time implementing this. Any help, VI examples, or guidance would be very much appreciated!

Thanks in advance!

[santo_13]

Why and how do these "2000" samples denote a complete signal?

Of course, you can create a 3-minute cycled capture, but I want to ensure you're doing things right if there is an additional reason why the number 2000

[wndulwlsp]

"The most important part of this signal occurs between 320 and 600 µs, and 2,000 samples are sufficient to capture it. So:"

1. "How can the time averaging feature of SignalExpress be implemented in LabVIEW?"

2. "How can a 3-minute loop be implemented?"

[mcduff]

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@wndulwlsp wrote:

Hi everyone,

I’m a beginner in LabVIEW and currently working on a project involving concrete mix testing. We're using a DAQ to acquire analog signals from two devices: a non-contact ultrasonic sensor and a Pundit tester.

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If you only have 1 DAQ, then you need to combine the AI acquisitions into a single task or perform the tasks serially.

1. "How can a 3-minute loop be implemented?"

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Your VI has no loops, so you need to add one. You would use a while loop. The while loop can exit when the user exits the program or an elapsed time is reached. I recommend a state machine.

1. "How can the time averaging feature of SignalExpress be implemented in LabVIEW?"

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Add your waveforms together that you acquire and divide by the number of acquisitions. Use a shift register on your while loop to keep track of the sum.

You would average your waveform instead