how do I set the ExTrig of a Basler A602f camera to falling edge?

[Bernd R.]

I'd like to trigger the exposure start on the falling edge of an external trigger signal. I use IMAQ 1394 Configure Trigger VI, but nothing happens when I change the polarity (true or false). Is it possible at all to control the camera via LabVIEW? Or do I have to use the Trigger_Mode control register as mentioned in the camera manual. I just don't understand how to do that.

Thanks
Bernd

[mhaag]

Bernd,

Thank you for contacting National Instruments. One thing to be sure to check when using the Configure Trigger VI is that the "Trigger Mode" is set correctly to the desired behavior. From the brief description you gave, it sounds like Mode 0 (or possibly 1 or 2) will be what you want for your application. By default, the trigger will run off of the falling edge. If you have not had a chance to look over it yet, glance through the help for Configure Trigger VI to see a description of the inputs.

There are also a number of VIs included with the IMAQ 1394 Driver that allow you to programmatically control the camera and set attributes associated with the driver. If you wish to change camera specific attributes, then you can use the IMAQ1394 Write Registe
rs VI (located in the IMAQ IEEE-1394 Low level subpalette) to change register level settings on the camera. You will need the camera documentation in order to know what register and information to write.

Depending on the camera, then all of the trigger modes may or may not be supported. The modes outlined in the help are valid for low-active polarity. If your camera needs to be specifically changed with a Trigger_mode control register, then you will need to read that information from Basler and then, if they have a configuration tool use that, or you can use the LabVIEW VIs to modify that register.

Regards,
Michael
Applications Engineer
National Instruments

[Bernd R.]

Thank you for your answer Michael. Do you have any example VI on how to use IMAQ1394 Write Registers VI? I don't know how to get the 0xF0F00000 representation of the address.

Bernd

[mhaag]

Bernd,

I have taken a look to see if I could find an example, and the only direct example I was able to come up with is written for Visual Basic. This example can be found at the following location:

Directly Accessing Camera Registers Using NI-IMAQ for IEEE 1394

As far as the address, then that information should be included in your camera documentation or available from the manufacturer. Also, remember to take a look at the help for those VIs to make sure you understand each input/output.

Regards,
Michael
Applications Engineer
National Instruments