Cameras are synchronized, but acquisition is not started simultaneously

Hello everyone, 

I have a problem after synchronization of 15 GigE cameras. Cameras are controlled in Labview and synchronized over Timestamp Modulo Event. They make photos simultaneously with accuracy up to 1 millisecond. But the problem is, that the acquisition is not started at the same time on all cameras.

For example, i make 5 photos of a stopwatch with a framerate of 1Hz. Some of the cameras captured e.g. following time on the stopwatch (Minuteseconds:Milliseconds):

00:01:00, 00:02:00, 00:03:00, 00:04:00, 00:05:00

while the other:

00:02:00, 00:03:00, 00:04:00, 00:05:00, 00:06:00

They are synchonized, but there is a delay of one photo.

Cameras with delay are not always the same, they vary after every start. Also the framerate has a big influence: the higher is the framerate the larger is delay. I.e. some cameras can start for example 5-6 and more photos later than the other. Only at the framerate of 1Hz there are no delays at all, but this is too slow for my purpose.

Is there a way to force cameras to start aquisition simultaneously? For example may be it is possible to add a condition that cameras wait until all of them are ready. Or may be it can be done in some other way?

Thank you,

 Vlad.