Frame trigger won't work with linescan camera

[jp1]

I am using an ISG Lightwise LW-SLIS-2048A-1394 firewire linescan camera along with LabView 8.0 and the IMAQ package. The camera is set up to use a hardware trigger for both the line triggering and the frame triggering. Although the line trigger works, the frame trigger does not. I spoke to the camera manufacturer, and they said that we are setting up the camera's registers properly. Also, the frame trigger works fine when using the camera manufacturers app, but it does not work when using LabView. It appears that the frame trigger is occuring randomly and ignores the frame trigger signal connected to the camera. The triggering vi does not have the appropriate triggering modes to do what I need to do, hence the reasoning behind setting up the camera's registers directly. Is anyone aware of this problem and can anyone offer any suggestions as to how I can get the frame trigger to work?

[T-Route]

jp1,
Thank you for contacting National Instruments.  Explain a little more about what kind of triggering you are doing.  It sounds like you are doing camera triggering which means you have an external signal connected to the trigger inputs on your camera.  If your camera is set up correctly to do triggered acquisition then you need only run the GRAB or sequence VI's in LabVIEW.  You do not need the trigger VI's.  If you are triggering the Frame Grabber then you need to set your camera to Free Run mode and in this case you will need the triggering VI's.  If you are using the cameras registers then I assume you are triggereing the camera.  In this case LabVIEW does not care about the trigger but only when an image has been passed in.  Please explain a little more.  Thanks and have a great day.

Regards,
Mark T
Applications Engineere | National Instruments

[jp1]

I am indeed attempting to trigger the camera with an external trigger line connected directly to the camera. I am not using the trigger VI, but was merely mentioning that it is not possible to do so because the VI does not support the triggering scheme we require. In addition to a frame trigger, I am also triggering each individual line on the camera. In order to put the camera into the proper mode, I must first set up the proper registers in the camera which are, by the way, are not standard DCAM registers and are outside of the DCAM register space. This setting up of the registers works OK, as I can read the values back. As mentioned before, the camera manufacturer has stated that I am setting the registers up properly, and everything works fine with their software. I am using the GRAB vi to get an image. I do get an image, but it is clear that the frame grab is not working. The trigger signal to the camera is a simple TTL level signal hooked up to a mechanical switch. There is an indicator light on the back of the camera which changes states when the camera receives the signal to begin a frame. This light toggles in conjunction with the mechanical switch when using the camera manufacturer's software. However, the actions of the light do not correspond to the mechanical switch when using LabView. Instead, the camera begins a frame grab, in what seems like a random fashion. The trigger line has no effect, and, in fact, the camera will take a picture even if there is no trigger signal at all when using LabView, regardless of how the registers are set. In addition, some other functionality that is set up by these registers also does not seem to work properly. It is important to note that the line trigger works and is set up with these same registers.

[T-Route]

jp1,
After you have the registers set up try to still use the 1394 trigger vi and see if it will work with one of the modes selected.  It sounds like the camera needs something else set because it is still passing image data even when you don't hit the trigger.  Are these registers set the same way when using the camera company's software?  How do you set the registers?  It sounds like something else is probably being sent to the camera to put it in the right mode.  LabVIEW waits for the image data to be sent so the camera is sending data when it is not suppose to.  Make sure the camera company's software doesn't set the camera mode also in initialization.  There is a 1394 trigger example you can try and a dx trigger example you can try in the example finder for LabVIEW.  Try these and switch the modes.

Regards,
Mark T
Applications Engineering | National Instruments

[jp1]

Mark T.,

Thanks for your help so far. When using the trigger vi, most of the modes give the following error:

"NI-IMAQ IEEE-1394: (Hex 0xBFF68008) Feature not present in the camera"

The only exceptions are "Disabled" and "Mode 0". Obviously, Disabled isn't intended to do anything. Mode 0 doesn't appear to do anything. Looking at the frame trigger indicator on the back of the camera, it is apparent that the camera is getting a signal to trigger, but it is not from the mechanical switch. The signal the camera is getting is not consistent. In other words, the trigger doesn't appear to be happening at a consistent time.

Trying to use the trigger vi as you suggested does not work, and seems to cause more problems with timeouts. It is hard to say exactly, because there is no consistency. The example program I tried doesn't really do much because the available trigger modes are not supported on the camera.

The registers are set up using the low level register write vi available in the IMAQ1394 palette. I am setting the registers up the way the camera manufacturer specifies. They have verified the values I am using. I have no reason to assume that their software is using anything else besides the registers they are indicating.

As for any interaction between the camera manufacturer's software and the camera, it is not possible. Their software will not work at all with the NI driver installed. They need a different driver. Their software does not run in the background or anything like that.

Thanks,

John

[T-Route]

John,
I am looking into this issue further and going to see what I can find out.  I will post with more information soon. 

Regards,
Mark T
Applications Engineering
National Instruments

[T-Route]

jp1,
After looking into the cameras user manual a little more it seems that Mode 0 for frame triggering is supported.  Can you set your camera up and just do Frame triggering by using the configure trigger VI on Mode 0?  If this doesn't work go ahead and post a very simple VI of how you set up your camera's registers and do the acquiring.  I'll take a look at it and try to see what is going on.  Thanks and have a great day.

Regards,
Mark T
Applications Engineering | National Instruments

[jp1]

Mark T.

Thanks for your help so far. I have created a few simple VIs for your inspection. However, I do not know how to post them, although I would like to. As for your suggestion, I tried the Mode 0 triggering, which from the description states "The camera starts integration on every falling edge of the external trigger input". However, with no external trigger hooked up to the camera, the image is happily snapped, with no complaints such as a timeout error. In other words, the camera does the same thing whether or not the trigger is disabled or in mode 1. Remember, that none of the other modes work with this camera. It should be noted that I power cycled the camera before attempting to trigger the camera using the trigger vi so that any of the registers I previously set up were reset to factory default values.

Thanks again,

John P.

[Allison_S]

John P.

    So are you saying that the image is taken even though it's not triggering?  That mode 1 behaves the same as disabled (or did you mean mode 0)?

    As far as attachments, below the Message Body window in the authoring window on the forums there is an Attachment section, there you can browse to a afile to attach it.

-Allison S.

Applications Engineering

[jp1]

Yes, I meant mode 0. Even with no trigger cable attached, the camera still takes a picture. There is no difference if the trigger is set to 'disabled' or 'mode 0'. The issue, however, is that I am trying to use two separate triggers, one for the frame and one for the lines, and that this should be set up by adjusting the camera's registers. The line trigger works, but the frame trigger does not.

I am attaching three VI's. One uses the IMAQ high level snap. One uses low level VI's to take the snapshot, and one uses the trigger VI to set up the trigger. The frame trigger does not work with any of them.

My thanks for taking a look at these VI's. Possibly, I am doing something wrong, but I am at a loss to see what that could be.

Your help is greatly appreciated.

John P.