sampled while loop

[Neil_Helsel]

I am using a NI 9401 mounted on NI cDAQ-9174 with a two digital fiber sensors attached. When something breaks the laser it sends a signal to the board. I am using this experimental code, playing around with a few things to try and get it so "see" one of each edge then stop.

I'm trying to get a while loop to end when one edge from each series is collected. Right now it ends on the "timeout" time. Any ideas?

[Richard_Ha]

It looks as though the DAQ task isn't created correctly. Can you include the "test.vi" that is initialiasing the DAQ task?

[Neil_Helsel]

Yeah here it is.

[Richard_Ha]

Is looks as though you've got the DAQ sample buffer set to 100 samples, and are then trying to read 1000 in one go

[crossrulz]

As a general rule, if you are using Continuous Samples, just leave the Samples Per Channel input on the DAQmx Timing VI unwired.  It defaults to a large buffer.  This just makes one less thing for you to worry about.

[Neil_Helsel]

Is there any way to set it up so the loop ends when two data points are collected vs a time.

[crossrulz]

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@Neil_Helsel wrote:

Is there any way to set it up so the loop ends when two data points are collected vs a time.

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I typically will send some type of command to tell the consumer loop to stop.  In this case, I would use an empty array as my stop command.

Nevermind.  I was thinking of another thread...

You can stop your collection loop based on whatever criteria you want.  If you are talking about running for X time, then I would keep a count of how many samples you have collected and stop when that number goes over the number of samples to cover your desired time.

[Neil_Helsel]

I'm sorry I meant right now I have it set to a time and want it to stop when a value becomes true for both DigitalIn_0 &DigitalIn_1.

[crossrulz · Accepted solution]

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@Neil_Helsel wrote:

I'm sorry I meant right now I have it set to a time and want it to stop when a value becomes true for both DigitalIn_0 &DigitalIn_1.

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Sounds like a simple AND when looking at the two channels.