- ActiViewScreenshot1.jpg (4.52 KiB) Viewed 15308 times
- ActiViewScreenshot2.jpg (4.71 KiB) Viewed 15308 times
Trigger Codes Missing Sporadically
Trigger Codes Missing Sporadically
I am running an auditory ERP task with e-Prime 2 Professional (version 2.0.10.356) on a Windows 10 OS (version 1709). In e-Prime, I have configured a task event to send a trigger label via the serial USB-Trigger Interface cable to a laptop with ActiView. The auditory stimulus occurs in a train of 4, followed by a longer inter-train interval. The train of 4 should consistently appear as follows in the ActiView trigger bar:
However, randomly, one of the trigger labels often fails to appear:
It is not always the same trigger label, and at other times, all of the labels appear without issue. With the USB-Trigger Interface cable, I was under the impression I did not need to reset the trigger label to 0 after each task event, but, just to troubleshoot, I tried this, but the issue has persisted. If anyone has any guidance / recommendations to resolve this problem, I would be very grateful. Thank you for your consideration.
-
Coen
- Site Admin
- Posts: 1148
- Joined: Fri Mar 26, 2004 7:00 pm
- Location: Amsterdam, Netherlands
- Contact:
Re: Trigger Codes Missing Sporadically
1) Set the trigger format (lower left corner) to "analog" to troubleshoot. You can then identify 16 separate lines (bits). Colored dots/bars indicate a that a line is HIGH. grey background indicate that a line is LOW.
2) Use positive logic: HIGH is trigger. LOW is idle (with negative logic, triggers may be missed when down-sampling/decimation in ActView is applied)
2) Pull all the (used) lines LOW between the triggers (often, only the lines 1-8 are used for triggers 0-255)
3) The trigger length must be longer than the hardware sample period (> 0.5 millisecond on 2 kHz sample rate), or else triggers may be missed.
Best regards, Coen (BioSemi)
2) Use positive logic: HIGH is trigger. LOW is idle (with negative logic, triggers may be missed when down-sampling/decimation in ActView is applied)
2) Pull all the (used) lines LOW between the triggers (often, only the lines 1-8 are used for triggers 0-255)
3) The trigger length must be longer than the hardware sample period (> 0.5 millisecond on 2 kHz sample rate), or else triggers may be missed.
Best regards, Coen (BioSemi)
Re: Trigger Codes Missing Sporadically
Coen,
Thank you for the prompt response. I followed your instructions but was still having some issues. I then tried changing the trigger signal command in ePrime 2 software, using a WriteByte command as opposed to a WriteInteger command. That seems to have solved the issue, with no further dropped trigger signals in the analog view mode. Thank you for your help!
David
Thank you for the prompt response. I followed your instructions but was still having some issues. I then tried changing the trigger signal command in ePrime 2 software, using a WriteByte command as opposed to a WriteInteger command. That seems to have solved the issue, with no further dropped trigger signals in the analog view mode. Thank you for your help!
David