Integrate external trigger into the camera (PCI 1424)

[Larry Liu]

Dear all,

I am using a PCI 1424 frame grabber to take image from one Kodak "camera".

Currently I set the camera to an continous mode--in which the camera give me frames one after one. I am able to "snap" or "grab" images in MAX with the help of the camera file. I can also write one simple VI to "snap" one image in LabVIEW.

Now I want to go to the camera's single capture mode. In this mode, the camera will output only one image at one trigger signal (the rising edge of a TTL singal).

I have wrote a short program to use parallel port to send this trigge signal to the camera. From the temporialy increase in the camera's supply current, I know that the camera captured one image.

however, the question is how do i capute this image?

What i am doing now is, to choose "snap" one image at the MAX and allow a wait time of 10s. After click the snap, i will go to LabVIEW and send the trigger signal to the camera.

however, in MAX, I altenativley got one white and black image, which is of coure a wrong image.

does any one know the reason?

and how should i integrate the trigger VI into the image captuire VI, so that I can finish the single capture task inside one VI?

There is one sample VI "Triggered Grab.vi" in which user can set the wait time and other properties for IMAQ1394, but i am not sure how to do it to PCI1424

thanks a lot.

[KrisnaWisnu]

Hi Larry,

Can you explain a bit more on how you use parallel port to trigger the camera? If its in LabVIEW kindly attach the VI. Also provide me with your software version (LabVIEW version, NI IMAQ version, Vision Development version).

I do not think you should acquire the image (snap) in MAX anymore, you should use LabVIEW instead to wait for a trigger and acquire the image when there is trigger and I believe you can use LL Triggered Snap.vi for trigger and snap, which can work with PCI 1424.

Sincerely,

Krisna

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[Larry Liu · Accepted solution]

Dear Krisna,

I have attached this VI.

LabVIEW 7.1

Framegrabber: PCI 1424 

Trigger the camera: after we set the camera into single capture mode (by hardware jumper), I only need to send one TTL signal and the camera will be trigger at the rising edge of that signal. So i program a pulse at the DIO 0 pin to output this TTL signal.

[KrisnaWisnu]

Hi Larry,

I would suspect there is a timing issue between your camera "snap" and your framegrabber "snap". Can you provide me with more details about your hardware setup (camera and the framegrabber connection)? Maybe some simple diagram would sufficient.

Sincerely,

Krisna

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[Larry Liu]

Dear Krisna,

Thank so much for your kind reply..

I have taken a look at LL Triggered Snap.vi.

It seems that the trigger signal in that program trigged the IMAQ (let me know if i am wrong, since i am new to image acquization).

in my application, it is the camera got triggered, and the IMAQ shoud ....somehow be prepared and wait for the frame from the camera to be captured.

[Larry Liu]

attached is my set up...

[KrisnaWisnu]

Hi Larry,

One thing that I want to confirm, in your hardware diagram, the parallel-port (for trigger) from PC is connected to Pin 95 or 96 or 97 or 98 of the 100-pin-cable right?

I think you should divide the VI into two:

1. Configure the camera for snap and wait for trigger

2. Send a trigger command

 
With the first VI you can use LL Triggered Snap.vi. Meanwhile for the second VI, you can create a new VI for parallel-port command separately. So you need to run the first VI, then when you want to acquire the image, you need to run the second VI.

Note: In LL Triggered Snap.vi, I think you should increase the timeout maybe to 10 seconds.

Sincerely,

Krisna

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[Larry Liu]

Dear Krisna,

the parallel port for trigger is NOT connected to any pin in the 100-pin cable.

On the camera board, there is one pin specially designed for trigger, so i connected the trigger cable directly from the paralllel port to the trigger pin on the camera board.....

I will try out your idea and update you the progress....

thank  you very much 🙂

Larry

[Larry Liu]

Hi Krisna

thanks a lot for your help.

I have figured out the problem.

it is not really on the labVIEW side.

when i only trigger the camera, the default exposure time is only 50ms--- and i cannot get the right image.

but if i program the camera to a longer exposure time, the problem is gone.

Thanks again for helping me to analyze the issue.