Recording repeatedly starts/stops when triggered via external TTL

[rry901026-cpu]

Hi,

I'm running into an issue with Open Ephys (GUI v0.6.7) and I was hoping to get some help.

Setup

• I use pycontrol to send a TTL pulse to start recording.
• The TTL output from pycontrol goes into the Open Ephys I/O board, which is connected to the acquisition board.
• The idea is: when pycontrol starts the behavior task, it sends a TTL, and Open Ephys should start recording at the same time.

Problem
When I trigger recording this way (via the external TTL from pycontrol), Open Ephys does start recording — but then the recording repeatedly stops and restarts on its own. This happens continuously during the session.

As a result, Open Ephys keeps creating many short recording files one after another instead of one continuous file.

However, if I do NOT use pycontrol and I just press "Record" directly in Open Ephys, the problem does not happen. In that case the recording is stable and I only get a single continuous file.

Question
Is there something about how Open Ephys handles external TTL-triggered recording start that could cause this start/stop loop? For example, does the TTL line need to be held high/low in a specific way, or should it be a short pulse instead of a sustained signal?

Any guidance on how the trigger signal is supposed to be formatted (pulse length, expected voltage levels, etc.), or how to configure Open Ephys to avoid repeated start/stop events in v0.6.7, would be really helpful.

I can also share a screenshot of the folder showing all the short recordings if that's useful.

Thanks in advance.

[anjaldoshi]

Hi @rry901026-cpu,

Could you share more details about how you're triggering recordings using TTL pulses from pycontrol? Specifically, are you using the Record Control plugin?

If so, you’ll need to set the trigger mode in the Record Control plugin to "Edge toggle".

Here’s a quick overview of the trigger modes:

• Edge set: Starts recording when the selected edge (rising or falling) is detected, and stops when the opposite edge is detected.
• Edge toggle: Starts recording when the selected edge is detected, and stops when the next edge of the same type is detected.

You can find more details in the documentation https://open-ephys.github.io/gui-docs/User-Manual/Plugins/Record-Control.html.

If you're not using the Record Control plugin and are instead using something like the HTTP server, please provide more information.