imaqdx simultaneous acquisition

[Carmo]

Hello All!!!

In this moment I'm triing to acquire snaps from 2 Dalsa Color Giga Bit Ethernet Cameras simultaneouslly.

My camaras are triggered with the same signal.

If I use only 1 cameras, my frequency is OK, but when I use both cameras my frequnecy is divided by 2 and my snaps aren't simultanoues. It´s seems that something is not working in reentrant.

My processor is consumed at  only 8% and my bandwidth is at 23% (fairway from the limits).

In attach you can find an example of what Im'm talking about.

Somebody know how can I solve this issue?

Thanks in advance, best regards,

Paulo Carmo

[BlueCheese]

Hi Paulo,

Please have a look at this thread from a few days ago regarding how to use the Grab VIs if you want synchronized acquisitions. You have to Grab by buffer number if you really want to acquire synchronized images from multiple cameras.

The other issue you are likely running into is that timed loops (which your VI uses) run in a single thread. This is necessary to achieve the strict timing they need. Thus, your frequency is dividing by 2 because you have 2 different Grab VIs that are running in serial and each is waiting for the "next" image. If you changed it to be by buffer number they would still run in serial since the timed loop uses a single thread, but the second one would return immediately because the image is already available.

In any case, the timed loop does not make a whole lot of sense in this program since the Grab VIs are running on their own timing based on the image you are trying to acquire and if it is ready. Essentially they pace the loop to the rate of the camera in the normal situation.

Hope this helps, 

Eric