When changing the exposure time in LabVIEW the frame rate drops

[Eule]

Hello

I'm using 2 GigE cameras (Basler piA640-210gm) to acquire simultaneously pictures with them. In principle, this works fine, but there are two things that puzzle me. Firtsly I want to be able to change the exposure time, the gain and the frame rate in LabVIEW. I can set this all in MAX and it works. When I change the exposure time in LabVIEW the frame rate drops. Iknow that the cameras ae able to handle these attributes and its also not a data streaming problem of the used computer. So what can I change here?

The other thing is, that the cameras are only acquiring at the same frame rate if I set exactly the same attributes for the exposure time for both cameras.If one has another exposure time than the other, its frame rate drops too. I really have no idea why that i so.

I added my code here for better understanding.

Thanks!

[BruceAmmons]

Most likely, you are running the cameras in a mode that does not use a fixed frame rate.  The camera just takes pictures as fast as it can.  This means if you set a long shutter time, there will be a longer interval between images (low frame rate).  If you set a short shutter time, you get a shorter interval (higher frame rate).

If you are setting a frame rate, the shutter speed is probably forcing a slower frame rate since it overrides the frame rate setting.  You should be able to determine the max frame rate by dividing 1000 msec/shutter speed.  You may have to use the manual to figure out how to convert the shutter setting to msec.  Likewise, you should be able to calculate a max shutter speed by inverting the desired frame rate.

Bruce

[BlueCheese]

Also, please note that you have both Get Image VIs in a single while loop. Since each will grab a single image each iteration you are essentially requiring that both cameras run at the same frame rate, although you are controlling the exposure/frame rate independently. You likely want to break this into two loops.

Eric