Why do I get the warning: "TriggerActivation property could not be set. Check the current value before continuing your work." when programmatically starting a video object?

I get an unusual warning now I have upgraded to Matlab 2018a. I am using a Ximea MQ042RG-CM with the gentl hardware adaptor.

To recreate the problem:

adaptor_info=imaqhwinfo;
cam_info=imaqhwinfo('gentl');
vid = videoinput('gentl', 1,cam_info(1).DeviceInfo(1).DefaultFormat);
vid.FramesPerTrigger=1;
triggerconfig(vid,'manual');
start(vid)

Which gives:

Warning: The TriggerActivation property could not be set.  Check the current value before continuing your work.

It appears to me that the TriggerActivation property cannot be set when the trigger mode is set to manual.

Can anyone help?

Thanks, George

[Carlos Jarro]

I have the same issue with a Ximea MU9. I try to see the preview of the video with preview(vid) and get the warning. Once you "check" the values it will show the preview normally. try get(getselectedsource(vid)) to check the properties.

Answer 1

[Luis Reinalter]

To set the trigger parameter the preview needs to be paused - try call "stoppreview(Cam)" before setting the parameter