1427 Loading?

[Unplugnow]

I am trying to trigger a strobe light via the TTL_TRIG(0) line on my 1427.  When the cable is actually connected to the strobe (15-pin D-Sub connector cable Pin 1 = signal Pin 9 = GND.  is at the 1427 end, and a BNC connector is at the strobe end), the software (any vision software, that is -  NI vision acq. examples, MAX, etc.) crashes with a Buffer Timeout error.  When the cable is unplugged, the software seems to run fine. I have done continuity checks on the cable, and it appears fine - no shorts, polarity correct.    I have also tested the strobe light using other TTL sources including low-current ones from other NI cards.  As a matter of fact, I have tested the strobe light without taking images using the TTL_TRIG(0) line on the 1427 and it works fine.  I have sent the TTL signal through a buffer as well and the same issue comes up.

Any ideas on what is causing the camera not to function when the TTL_TRIG(0) signal is hooked to the outside world?

[Jaidev]

Hi Unplugnow,

Looking at the error (Buffer Timeout), it looks like the card is being set-up for triggered acquisition. Which means that it is waiting for an input pulse on the trigger line to start acquisition.

Heres what you have to do in order to drive (output pulses) the trigger line:

1. In MAX, navigate to the "Signal Levels" tab for your camera. Set signal level for the desired trigger line to "TTL In/Out". This setting doesnt determine if the line is and input or output, just that its not an isolated input.

2. In LabVIEW, use the IMAQ Trigger Drive2.vi to configure which signal you want to drive the trigger line with.

3. Try the following inputs for the VI (just a guidline based on my understanding of your app)

Trigger Polarity: High True

Trigger Type: External

Trigger Number: 0

Trigger Drive: Vertical Synchronization Signal (This signal is asserted before every frame)

Let me know if this helps.

Jaidev

[Unplugnow]

Jaidev,

I have tried the various tests you have described in my troubleshooting process.  No luck.  Based on other testing I have done, I think the problem might be an incompatibility with the 1427 and some third party hardware, not the 1427 itself.

I am working with the camera vendor now to help troubleshoot the process.  If I find anything NI related, I will post it here for anyone else that might have the same problem in the future.

Thanks for your time!

Unplugnow

[Unplugnow]

OK.  It looks like I was having bad hardware issues and have resoved those with the vendor, but, basically, nothing else has changed.

I am trying to use a 1427 CameraLink card connected to a Basler A202k camera.  I also need to trigger a strobe light (using a TTL signal) using some sort of frame synching. There are no other inputs or outputs to the camera besides the CameraLink cable.  I am trying to use the default settings in the camera file and the default settings in MAX for this camera.  The current setup is as follows: 1427 card tied to the camera.  The TTL_TRIG(0) line and a DGND line are tied to an optoisolator (LED and resistor) on a breadboard.  The output of the buffered optoisolator is connected to the TTL Trigger Input of an Oriel strobe light.  I am running LL Trigger Drive.vi.

When I attempt to run LL Trigger Drive.vi with the strobe light disconnected from the output optoisolator, it runs fine (that is, a status LED blinks at the output of the buffer).  When it is connected, however, the strobe light fires once and then the software times out (No Acquisition in Progress). 

I have tested the strobe light (with and without the optoisolator) using the digital outputs from a PCI-6024 at speeds of up to 50 Hz and it runs fine.  I have used an isolation transformer on the Strobe light power supply with no effect.

I think the problem might be in my misunderstanding of the signal requirements for the system as a whole.   Given the setup above, how, specifically, do I trigger the strobe in synch with the Start of the Frame?  I looked at the Knowledge Base stuff, but it seemed too generic for me to apply.  I have attached the text of the camera file I am using.

Thanks in advance.

[Unplugnow]

As I said, I would re-post when the problem was solved.

The short story is the high-power Oriel strobe light was causing two problems: 1) Spurious RF interference via the 15-pin pigtail to BNC trigger line when the trigger cable was connected to the 1427 but not connected to the strobe and 2) "Ground bounce" when the trigger cable was connected to the strobe.

We switched to another strobe and the problem has gone away.

[AnalogKid2DigitalMan]

Unplugnow (guess that's what had to be done with the old strobe)

Good troubleshooting, thanks for posting the solution!

-AK2DM