!!!help!! why my while loops are not synchronized????!!!

[qian.ma1@ucalgary.ca]

Hi everyone,

I want to acquire images from all 8 cameras synchronized with the sampling rate of 1sample/sec. I use 'Wait Until Next ms Multiple' to determine the sampling rate. And indicators of each while loop iteration are used to see whether the acqusitions are sychronized.

Attached, '8cam.vi',  is my present code. 

According to my frame grabber manual, one RTSI trigger can only synchronize 4 devices. So I used 2 different trigger line.
Now the problem is, I wanna increase the sampling rate up to 1sample/ms. But I can't. The indicators of each while loop iteration won't be the same after few iterations like this:

Can somebody please tell me why it fails ?? ?? 

Following is the hardware info:

My cotroller is pretty old so I'm wondering if it is the hard drive problem. 
Frame grabber device: PCI-1428;
Chasis: NI PXI-1045
Embended Controller: PXI-8196 (with Intel Pentium M processor）
Frame grabber: PXI-1428 (with upload memory of 32MB each)
Camera: DALSA Piriha2 line scan camera

[RTSLVU]

My first guess is the IMAQ Sub-VI's or whatever (I don't have the toolkit) are not set to be Reentrant so your loops are not really running in parallel.

[paul_a_cardinale]

If you want everything in the loops to be synchronized, then why put it into 8 loops.

Why not just use one big loop?

Also, those sequence structures don't seem to be doing anything.

And I would put most of the code in inlined-Sub VIs.

[qian.ma1@ucalgary.ca]

Hi,

Thanks for replying.

That was my first guess as well. But I've checked the VI properties, it is set to be Reentrant actually.