# The default Start-Stop Trial rule

How to access the Start-Stop Trial rule

▪Choose Setup > Trial Control Settings > Open and select an existing Trial Control Settings.

▪In the Experiment Explorer, click one of the Trial Control Settings.

With this rule, you control the start and stop of data acquisition (tracking).

What the Start-Stop Trial rule means

The sequence of boxes A to F can be read as follows:

1.When you start the
trial, for example by clicking the Start Trial button, the box A (Rule Begin - Start-stop trial) is activated. Control passes immediately to the box B.

2.EthoVision XT checks that the
condition in the box B (Condition - In Zone) is true. The condition states that the center point of the subject (or of any subject in the same arena) must be detected in the arena for an uninterrupted period of one second.

When you start the trial and the subject is not yet in the arena, the condition is false. EthoVision XT waits until the subject has been detected for one second. At that time, the condition becomes true. Control passes immediately to the box C.

note In special cases this box is absent or has different settings. See The start-stop trial rule in special cases

3.When the condition B becomes true, the box C (Action - Start track) is activated, and
tracking starts.

4.Control passes to the box D (Condition - Time). EthoVision XT checks that the condition is met. This condition is set to wait indefinitely, so that tracking stops when you give the stop command, or when the end of the video file has been reached, or when the maximum trial duration has been reached. See Control the end of tracking

5.When one of the events specified above occurs, the box E Action - Stop track marks the end of the tracks in the arena.

6.The box F Rule End - Start-stop trial marks the stop of the trial; it does not take any action.

Notes

▪If the condition in box B is not met immediately, the time that tracking starts (C) is different that the time that the trial starts.

▪The Start-Stop trial rule only works when you acquire data (live or offline). If you only record video, the Start-Stop trial rule is inactive. You must start and stop video recording manually.

See also

▪Trial vs. track

▪How the trial control instructions are executed

▪The start-stop trial rule in special cases