Knowledge Base

Problem

When attempting to start a trial or experiment acquisition, EthoVision shows the message 'Checking start condition' and does not proceed.

Details

This occurs when the trial control settings include a start condition (e.g., a hardware trigger, TTL input, or logical condition) that has not been met or is misconfigured. The software waits indefinitely for the condition to be satisfied before allowing acquisition to begin. Affects EthoVision XT across multiple versions.

Solution

1. Go to Trial Control settings for the affected experiment.
2. Review the Start Condition configuration. Check whether it requires an external trigger (e.g., TTL input, IO box signal) or a logical/variable condition.
3. If an external trigger is configured but not connected or not firing, either connect the appropriate hardware or change the start condition to 'Immediately' for testing.
4. If a condition variable is used, confirm the variable is being set correctly before the trial starts.
5. Save the trial control settings and attempt to start the trial again.
6. If the issue persists, simplify the start condition to 'Immediately' to confirm the rest of the experiment is functional, then re-add the desired condition.