trigger a camera using M series DAQ

[sukanya]

Hi

I need some pointers on how to proceed with the following issue. I currently have a setup where a CCD camera takes videos and stores them as .avi files for a specified time duration. I want to modify this VI in such a way that the camera gets triggered externally by using M Series DAQ (NI-PCI 6221). So now I want the camera to get triggered every one hour so that it takes videos for 30 seconds and stops. So could you tell me how to proceed?

Thanks,
Sukanya

[Wes_P]

Hi Sukanya,

Thanks for posting on the NI forums!  Triggered image acquisition is possible most of the time.  However, it may be dependent on your particular system.  What kind of camera interface are you using? (FireWire, GigE, Analog, CameraLink, etc.)  The way to go about setting up the trigger will vary depending on which type of interface you are using.  If you are using a framegrabber board, you will be able to set up triggering using the IMAQ VIs in LabVIEW.  If you are using a FireWire, GigE, or CameraLink camera, triggering capabilities will be dependent on the camera.

Wes P
Applications Engineer
National Instruments

[BruceAmmons]

If you only need to take a series of images once every hour, I doubt you need precise hardware triggering.  I would probably just use a timer in software that checks the elapsed time.  When you get close, you could set up a msec delay and start the acquisition within a fraction of a second of the desired time.

Bruce

[sukanya]

Hi

There is a slight change in the requirements. I actually want to take snapshots every one hour and this will go on for 24 hours. If it is a software trigger would it be precise? If the computer gets some other high priority interrupts, this trigger might not be precise right? I actually want to do this with a function generator.

Thanks
Sukanya

[Wes_P]

Hi Sukanya,

You are correct that using a non-Real Time operating system will not be deterministic.  That is, you cannot predict when other tasks (such as mouse input, keyboard input, email checking, etc.) will be scheduled.  However, since you are only needing to take a snapshot every hour, I don't think that this will be a problem for you.  You can still measure milliseconds from your system clock.  Thus, you can be sure that whenever 3600000 milliseconds (1 hour) elapses, you will accurately be at 1 hour.  In short, since the time delay that you are using is so great, software timing should be completely sufficient.

Wes P
Applications Engineer
National Instruments