Vision Acquisition Express VI error

[Abeer146]

Hello

I am new in labview and I am using the Vision Acquisition Express VI in a while loop. When I run the code, I get an error message " NI-IMAQdx: (Hex 0xBFF69004) Invalid camera session".

Please help me

[mikeporter]

Which iteration? If it fails from the very first its likely that the express VI is not configured correctly. If it fails on subsequent iterations there might be a problem using the express VI in a loop (never use express VIs inside loops).

Mike...

[Abeer146]

The first iteration, these are the steps that I follow:

• Vision and motion -> vision express -> vision acquisition
• Select acquisition source – I select my webcam
• Select acquisition type – I select continuous acquisition with in line processing /Acquiring image type -  Acquiring most recent image

• Configure image logging settings – disabled
• Select controls/indicators – control: stop / indicator: stopped and image out  

[natasftw]

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@mikeporter wrote:
(never use express VIs inside loops).

Mike...

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It's better to avoid using the word "never."  The DAQ Assistant makes more sense within a loop.  Instead of never, you'd be closer to saying always use it.  Elapsed Time is an express VI.  How would that make sense outside of loops?

[cody_a]

Are you using a USB 2.0 webcam?  Are you able to use the camera to acquire images in MAX?  In the "configure acquisition settings" step of the Vision Acquisition Express VI setup, are you able to acquire images with the "Test" button?

Based on your description, it sounds like you configured the express VI correctly, so I'm wondering if there are problems with acquiring from the camera at all.