07-22-2014 06:00 PM
Hi,
We are trying to trigger a CCD camera for capturing image at certain frequency. Our hardware setting is as follow: we have NI PCI-6281 DAQ card installed on the computer. It connects to BNC-2110 box. The trigger output PFI 12/P2.4 on BNC-2110 was connected to a CCD camera through a 12-Pin Hirose female to BNC cable.
To test whether the triggered image capture works properly. We used Gen Dig Pulse.vi and Triggered Grab.vi. The triggered image capture did work, but it does not work at the desired frequency set by us. I assume the frequency is (1/(high time + low time)). Any suggestion?
Thanks.
07-22-2014 07:31 PM
07-23-2014 01:17 PM
Hi Mike,
Right now I'm just testing whether the image capture is at the frequency I set. For example, when I set high time = 0.5 s and low time = 0.5 s in Gen_Dig_Pulse.vi, I expect the image capture frequency is 1 frame/s, cause 1/(0.5+0.5)=1Hz. But it actually captures image at 2 frames/s. It appears that the frequency = 1/hight time, since changing the low time value does not affect anything.
Thanks.
Jun
07-23-2014 01:58 PM
This answer doesn't make sense. If what you say is true, the camera isn't really synchronized with the clock.
What happens if you set the off time to a very long time like 20.2 seconds. Do you see a new image every 20.7 seconds, do you see two images captured close together then a long gap before the next 2?
Mike...
07-23-2014 04:40 PM
Yeah, it doesn't make sense. I don't think the camera is the problem. I did some test to check the trigger signal generated by Gen_Dig_Pulse.vi by using Acq&Graph Voltage-Int Clk.vi to see the signal. I saw a clear squared periodic signal (which is what's supposed to see) at the frequency decided by only the high time value in Gen_Dig_Pulse.vi settings. I kept the high time value the same and changed the low time value to up to 10s, it didn't affect anyting. The periodic squared signal shows up at constant frequency as set by the high time.
07-23-2014 05:47 PM