1409 cannot read variable shutter KP-F2A

[Tom Hanna]

We have a hitachi KP-F2A camera plugged into a 1409. The camera works fine in untriggered mode, and in triggered mode with fixed shutter speed. However, with fixed shutter speed not all the image is captured - the image moves randomly up and down, and some black is captured in the image, above or below the part-photo. We are driving the camera and card off separate (Synchronised) digital pulses. Adjusting this synching changes the average position of the picture but does not stop it jumping about. Does anyone know why this might be?

We are trying to use the camera in variable shutter speed mode (frame on demand on, fixed shutter slider off). When we put the camera in this mode, we get a 'cannot lock to camera' error (1074397153
). Does anyone know why this might be?

Many thanks,

TomH.

[Amaury]

Tom,

It sounds like you are trying to trigger the camera Assynchornously, but you do not have the 1409 set up in external lock mode.

That is to say, If you are triggering the camera, you are reseting all of the timing signals with the tirgger edge, normal singal locking circutry will end up giing you all sorts of gabled and scrolling images as you are seeing since it will aquire based on the synch signals from before the trigger.
This tutorial should get you a bit farther:
Advanced Analog Triggering and Synchronization Techniques

Regards,
Amaury Rolin
NI Applications Engineer.

[Tom Hanna]

Thanks Amaury,

We've tried ext lock, as well as ext lock HV and ext H lock (which is the 'H-lock only' referred to in the tutorial?). In this mode we get a timeout error at grab buffer. We are wondering about the synching signals - on the KP-F2A, in trigger mode there is nowhere to drive the camera with the signal from the card, nor anywhere to output the H and V synch signals from the camera itself. The only signal we get is the video signal itself - which has the HSYNC on it, to be sure, but doesn't seem to do the job. What connections are needed to communicate the synching signals? We have just been sending the video signal through the BNC connector - we have ordered the high density connector though, and should have it soon...

I've also at
tached the latest version of our file, in case you can spot an error in that which leads to the timeout.

Many thanks again,

TomH.

[Amaury]

When not using the standard modes the synch signals need to be cabled seperately through a 778135-01
IMAQ-A6822, 22 BNC Connector Block with attached 1m cable otherwise you will definately get a timeout.

If you need to generate the synch signals from the card, genrate them using the external trigger lines of the 1409 with the IMAQGeneratePulse VIs.

You might want to look at an app note such as the one for the Sony XC-55 to get a better idea of what is involved in Asynchronous Triggering 

Regards,
Amaury

[Tom Hanna]

Hi Amaury,

We've looked at those examples - the problem here is that in triggered mode, our camera has nowhere to input the synching signals - the HD channel is left blank, the vertical is used for the trigger. We've written to the camera vendor, asking about this.

Many thanks,

TomH.

[Amaury]

Tom,
I can't find the pinnout to the camera from Hitachi, but they do mention External sync operation with HD/VD 4to 6Vp-p....so you should have somewhere to cable up to that! Hitachi should be able to tell you better than I can!

Regards,
Amaury

[Tom Hanna]

Hi Amaury,

I'm feeling like we must have exhausted every option by now, but we're still not having any success.

We have extracted the H and V synch from the signal, and fed them to the 1409 board. It still complains that it cannot lock to the video source, or just times out on us. We cannot run the camera in continuous mode with the board on external H or HV lock.

I have tried using the Sony XC55 example. For a while there I had it taking some sort of image, but it was rather garbled, maybe a third of a frame, and stopped working after I tried another VI before returning to it. I have tried the VSynch from the camera (one trigger mode) and the WE pulse (fixed shutter and one trigger modes) without but neither seems to work.

When the camera is in trigger mode it does not output synch signals - nor can it receive them. This was why we got the synch splitter. However, the card doesn't seem to be able to run the camera in ext lock mode, even with the camera in continuous mode.

This is some of an email sent to me by one of the Hitachi tech support people. I have also attached the KPF2A manual.

Many thanks,

TomH.

I believe the problem you are having is the frame grabber ability to lock to
the incoming video. In a triggered mode of operation, the video signal from
the camera is not constant, so the frame grabber does not have a continuous
reference of vertical sync in order to properly position the image. In the
one trigger mode, the video signal is only present after the trigger pulse.
The frame grabber sees the incoming video frame and has to quickly lock to
the vertical sync to properly frame the image on the monitor. If the frame
grabber is slow to lock or misses a couple of vertical interval pulses, the
displayed video will be shifted on the monitor.

In the case of the Fixed Shutter mode, there is no vertical sync on the
output video, so the frame grabber has a greater problem when trying to
properly position the image.

The camera has a WE (Write Enable) pulse that can be used to tell the frame
grabber when the next frame of video is coming from the camera. This pulse
is output from pin 2 of the 6 pin connector prior to the output of the video
signal. This should make it easier for the frame grabber to lock to the
single frame of video that the camera outputs in the triggered mode.

In both modes of frame-on-demand, the external sync signal inputs are not
active. The trigger pulse is always input on the VD line (pin 7). The
actual trigger for the camera always occurs at the next HD drive pulse, so
there can be a maximum 1H delay between the application of the trigger
pulse, and the time the camera begins the actual exposure. In the one
trigger mode, there can also be a maximum 1H delay between the end of the
trigger pulse and the exposure duration.

The operation of the camera cannot be changed, so it may be necessary to
work with NI concerning the timing and the capture of the video. Hitachi
can supply a camera to NI if they need one to help in solving this problem.