How can I identify a trigger signal into NI 1428?

[gistguy]

Hi

I would like to insert trigger signal into image grabber board(ni 1428).

So, I made TTL pulse(PWC) and inserted it into T0(VINIT) in NI 1428 connector.

But...

Camera(Pulnix, tm-6740cl) didn't work by triggering. It means that grabbed image was only shown corresponding to parameters in MAX(exposure time, electric shutter mode)in regardless of  trigger signal.

I don't know about this problem.

How can I know the fact that inserted trigger signal is transferred through camera link cable on labview program?

Do you have some vi.?  My labview version is 7.0 express.

and..

I have to get an one image with long integration time. For example, my camera frame speed is 200fps. but I don't have to get an image at  this speed. Lower frame speed(100fps or 50fps so on) is needed for me to get an image at first time.

That's why I would insert trigger signal(100Hz or 50Hz) into frame grabber. You know, shape of TTL pulse is important for me.

Let me assumet that tm-6740cl camera expose pixels during TTL 0V(falling edge) and read out cluster of electrons during TTL 5V(rising edge). I think that image can not be gotten during read out time(TTL 5V) and it means that  when we wanna get  4 images for moving object continuously, we can't get images of moving object during read out time(TTL 5V).

I have to get 4 images of moving object during one period.

To do this, exposure must begin when object begins to move simultaneously. When exposure time is 1/4 time of object period, ccd camera have to read out accumulated electrons  swiftly. At the same time, second exposure begins and when this exposure ellapses 2/4 time of object period, second accumulated electrons are read out by CCD camera. This process continues until moving object has one cycle.

Finally we can get 4 images for moving object.

How can I make TTL pulse to do this? That' all what I wonder.

To explain in detail, I posted attachment.

Thank you.

[DJ_L.]

Hey gistguy,

First, you can use the trigger inputs on the 1428 board to connect your TTL pulse. Use the TTL_Trig0 input pin to connect your signal for example. One thing you have to be aware of is you can not use triggering in the MAX environment. So if you were trying to trigger in MAX, you would not be able to. You can, though, set up and use triggering in a software environment such as LabVIEW. There are some good examples that ship with the NI-IMAQ driver. You can use the NI Example Finder to find these examples. One good example for triggering would be the LL Triggered Ring.VI example.

Now regarding your trigger pulse that gets sent to the camera. So what is going to happen when you trigger the 1428 is that the board will then know that it needs to send a pulse to the camera in order to acquire the image. This pulse needs to be set up in your camera file, and this means that the pulse is going to have a set pulse width. This pulse width can be the length that your camera needs to know to expose for a certain amount of time, and when it is done exposing for that time, then send the image. Now you said "I have to get 4 images of moving object during one period", I am assuming that you want the camera to get exposed 4 times and send one image with 4 images in that one image. To do this, your camera would have to have this functionality to be able to take 4 images on one rising edge of a trigger input. The 1428 can only send a signal to the camera. What the camera does with that signal is dependent on the camera. Now if you want the 1428 to send 4 pulses to the camera to take 4 images at specific times, then we can do that, but if you are only sending one pulse to get 4 images, then you might want to contact the camera manufacturer to see if your camera can do that.

If you want to change the pulse width of the pulse that gets sent to the camera, then you might need to consider a different frame grabber. For example, if you need to route a signal from the Trigger input to be sent to the camera, the 1428 cannot do this. The 1426 and 1429 can do this, but the 1428 has a pre-determined pulse (defined in the camera file) that it sends to the camera when it receives a trigger input. But this does not sound like what you want to do. What I think you want to do is either send one pulse each trigger input, or maybe you want to send 4 pulses for each trigger input. You would have to set the 4 pulse attribute in the camera file. You can use the NI Camera File Generator to alter your camera file to do this if you would like.

Last, take a look at the tutorial called Trigger Each Buffer or Buffer List. You might want to consider using the Trigger Each Buffer List because it uses the trigger to capture repetitive events which are longer than a single frame in duration. This kind of sounds like what you want to do, so check out the tutorial and examples that are linked to the tutorial. This might give you an idea of how to set up your system.

I hope this helps you out at least a little bit, or gets you started. If it does not, then maybe I did not understand correctly what you are trying to do. In that case please try to explain what you are trying to do a little more. Please let me know if you have any questions or concerns. Thanks, and have a great day.

Regards,

DJ L.

[gistguy]

Thank you for advising me.

You mean that before I insert a my own trigger sgnal(PWC) into T0, I have to set up Pulse Width tha I would like insert in camera file?

Your guess is right, I will get 4 images by tm-6740cl whch is triggered by continuous 4 pulse signal, not an image with 4 images.

Meanwhile, I have a curious question for conventional CCD camera like tm-6740cl.

In case of PWC(Pulse Width Controlled)signal, frame rate time is (exposure time + transfer time)

During transfer time, can CCD camera expose the pixels simultaneously like my attachment?

My CCD camera's transfer time is 5msec. So, I think that information of image for 5msec(readout time) can't be gotten and the image is lost,

Is it right?

[DJ_L.]

Hey gistguy,

To answer your questions:

Q: "You mean that before I insert a my own trigger sgnal(PWC) into T0, I have to set up Pulse Width tha I would like insert in camera file?"

A: If you want to send a signal to the camera that triggers the camera when you trigger the board, then you have to have configure your camera file to do this. You will want to configure the signal pulse in the camera file to do this. Then the board will send the pulse that is configured in the camera file to the camera when the board is triggered.

Q: "In case of PWC(Pulse Width Controlled)signal, frame rate time is (exposure time + transfer time) During transfer time, can CCD camera expose the pixels simultaneously like my attachment?"

A: The answer to this question should be in your camera documentation.

Q: "My CCD camera's transfer time is 5msec. So, I think that information of image for 5msec(readout time) can't be gotten and the image is lost, Is it right?

A: Again, if you are looking for specific information about your specific camera, then you will most likely be able to information about whether your camera can do this in the camera documentation.

Last, if you are going to trigger the board, I would suggest that you trigger the board 4 times so that the board sends one trigger each time it receives a trigger, therefore it sends 4 triggers, and the camera sends 4 images. The other option that you have is to set up a signal in the camera file that sends 4 pulses to the camera, and only trigger the board once in the beginning. 

Let me know if you have any further questions. Thanks, and have a great day.

Regards,

DJ L.

[changle0204]

I saw your reply and learn a lot .I have a similar question. pcie 1430 and camera  silicon imaging 11300MH-CL 

I want to trigger each image with labview program .The CC1 in the camera link is said to be used to trigger the camera ,and the camera itself have a trigger line, which one have to use.

Then, I can decide with IMAQ trigger3.vi  which type of trigger to use , what is the different between external and ISO in. which one is from the SMB port.

I am sorry for my silly question.

[changle0204]

I read your reply and learn  a lot . PCIE 1430 camera silicon imaging 1300MH_CL

I want to trigger each images continuously ,  the CC1line is said to be trigger the camera ,but the camera itself have a trigger line.so which one to use.

I can choose which type of trigger to use with IMAQ configer trigger3.vi  but what is the difference between external and ISO in .which one is coming from the port SMB .

can you give me some information or examples about my problem . oh  , I do not have a RTSI cable .