CXPSingleCamera output empty image when no trigger signal input.

    A CXP Camera can usually be configured either to be in "free run mode", or to be slave of the trigger signal.

    You should look into its genicam configuration.

    With MicroDisplay, you can use Tools > GenicamExplorer, and look for nodes :

    Acquisition Control> Acquisition Mode (something like "Continuous" means "free run", and the camera use its "Acquisition Control > Acquisition frame rate"). If you set the Acquisition mode to "CoaXPress", you can be enslaved to triggers coming from the OptoTrigger, for instance. Some cameras may also have "Single Frame" or "Line 0", when using native ports (not CoaXPress) for the trigger, documented by the manufacturer of the camera.


    For some cameras, it will be rather "Acquisition Control > Trigger Mode" and "Acquisition Control > Trigger Source"


    CXP-trigger.jpg

    Below you can see a simple VA design in order to check if the trigger is working as expected:


    BRudde_Paranoid.png

    BRudde_mE5MA_VCX-QP_Single_Capture.va


    The idea is to count the number of send line triggers versus the number of received lines.

    By this TriggerMismatch.Status should show a small value juming in between of 0 and 1 for low line rates.

    Only in case of special line scan cameras or higher line rates the plausible value is in between of 0 and N,

    where N is the amount of lines that is "stored" inside the camera or currently in transfer.


    In case of an area scan camera this will not work as expected, but it can be modified correspondingly:

    FrameEndToSignal, 2D links...

    Quote from Bjoern.Rudde

    The idea is to count the number of send line triggers versus the number of received lines.

    By this TriggerMismatch.Status should show a small value juming in between of 0 and 1 for low line rates.

    As soon as we know that the line trigger is producing the expected amount of lines:

    We can check how the external image trigger is working...

    In my application, some time encoder will be shock when the motion stops. So I used ShaftEncoderCompensate to offset the reverse pulse.


    The goal is that camera(line scan) doesn't output line(image) when the motion stops.


    In this design mE5MA_VCX-QP_Single_EncoderTest.va , the received lines counter still increase [Test video].


    Why is there no trigger signal input but still received lines from the camera?


    Thanks!


    Jesse

    Dear Jesse,

    Quote from Jesse Lin

    Why is there no trigger signal input but the camera still outputs the image?

    Please check with the VA design I posted above, if the line scan camera and the line trigger work as expected.

    1. Configure the line scan camera for external trigger.
    2. Send CXP trigger signals to the line scan camera.
    3. Check if Amount of triggers matches the received number of lines.

    If the line trigger works as expected, then we can go one step further.

    Then we can use the ShaftEncoder direction and use this as a mask for the image trigger and/or transfer.

    Dear Jesse,


    Thank you for your efforts.

    Quote from Jesse Lin

    In this design mE5MA_VCX-QP_Single_EncoderTest.va , the received lines counter still increase [Test video].

    I watched the video and the camera is sending lines, while no trigger is send.

    If you want, you can use Select operator and Gnd to detatch the trigger completely in front of the camera.


    Since the VA design is receiving lines at a certain rate - from the video I would suggest around 1 Hz - this seems to be a feature of the camera.

    So the camera configuration needs to be investigated.

    Hi Bjoern

    Quote from Bjoern.Rudde

    Dear Jesse,

    Please check with the VA design I posted above, if the line scan camera and the line trigger work as expected.

    1. Configure the line scan camera for external trigger.
    2. Send CXP trigger signals to the line scan camera.
    3. Check if Amount of triggers matches the received number of lines.

    If the line trigger works as expected, then we can go one step further.

    Then we can use the ShaftEncoder direction and use this as a mask for the image trigger and/or transfer.

    This is your design result [Test video].

    1. Yes. It is external trigger mode.

    2. In your design trigger signal is period.

    3. TriggerMismatch.Status is jumping between of 9 and 10.


    Jesse


    Thank you.

    Quote from Jesse Lin

    This is your design result [Test video].

    1. Yes. It is external trigger mode.

    2. In your design trigger signal is period.

    3. TriggerMismatch.Status is jumping between of 9 and 10.

    In this video we can see that the external line trigger is working as expected, in case we are sending it.

    This is showing that the line trigger and the camera response work together.


    But there are two questions now:

    • Why there is there a mismatch of 9 to 10 lines?
      • What kind of sensor (Dual-Line, Multi-Line, TDI, ...) is used?
        For example a TDI with 8 stages could be the reason for 8 triggers being required for the first line feedback...
    • Why do we receive lines while not sending triggers?
      • This may be a camera feature, but I have no explanation for that.

    From my point of view both questions are something where the camera manual or the camera manufacturer support can give an answer. Is it possible to mention the camera name/manufacturer?

    Hi Jesse,


    I looked through the camera manual and I found no mentioned reason why the camera should send unmotivated lines in external trigger mode, while no trigger is send.

    You have to contact the camera manufacturers support for more details on this.


    From the VA design perspective I do not see an obvious reason for these unmotivate lines.

    Hi Bjoern


    I have confirmed with camera manufacturers support this issue that was the camera sensor problem.

    The camera is operating internally and will send one line in external edge mode.


    Thank you for your reply.


    Jesse