Knowledge Base

Sub-Rules (Continued)

Configuring Sub-Rule References

To configure how a sub-rule repeats and starts, use the following options:

• Start to Start: To keep a constant time between the start of successive repeats. For example, start repeats at every hour. Enter this time in the corresponding box (hh:mm:ss).

10. Select one of the options to specify what to do when a new start condition becomes true and a previous repeat is still ongoing. For details, see Options for Starting a New Repeat.
11. Under Comment, enter a description of the sub-rule reference (optional).
12. Click OK. The reference box is displayed on your Trial Control screen.
13. Insert the reference box in the appropriate place in the Trial Control sequence (this can be either the Start-Stop trial rule, or another sub-rule).

Notes

• If you want the sub-rule not to start immediately as its Reference becomes active, select Without Delay and click the Delete button.
• If you accept the default options (Without Delay in the Start conditions box and one repeat), the sub-rule starts immediately and is repeated just once.
• You cannot edit a condition that you have added to the Start conditions box. Delete the condition first (select the condition and click the Delete button), then click Add to add a new condition.
• The Start conditions are listed in the following order: Without Delay, Delay, Clock Time, Trial Control variable.
• Stop to Start of a Repeat: There is always at least 1 sample difference between the time that the Rule End box is evaluated and the time that the Rule Begin box is evaluated for the start of a new repeat. This means that a new repeat can never start exactly at the same time as the end of a repeat.

Reference Names

Names of sub-rule references must be unique in your experiment, unless you have re-used an existing reference. You cannot define two sub-rule references with the same name, even when these are defined in two different Trial Control Settings. This is because analysis of Trial Control data is based on names of elements (sub-rules, references, actions and conditions). Elements with the same name would give ambiguous results.

Re-Using a Sub-Rule Reference

If you choose to create a copy of a sub-rule reference and then change any property of this copy (Name, Reference options, or Comment), a window appears with the message Define the scope of your changes. The program asks you whether you want to apply the properties only to the newly-created reference, or to the references with the same name in all Trial Control Settings. Choose the option you require and click OK.

If you re-use a Reference that is stored in another Trial Control profile, and this profile is locked after data acquisition, changing any of the Reference settings will not affect the Reference in the locked profile.

Modifying a Sub-Rule Reference

To modify a sub-rule reference, click the Settings button in the reference box.

Multiple References to One Sub-Rule

You can define multiple references to the same sub-rule, and place the corresponding Reference boxes in the same Trial Control sequence. In the case they are activated at the same time, the program executes the sub-rule in two parallel instances. Such instances are independent; however, they can interfere with each other if they both contain actions on a Trial Control variable or on hardware devices.

Endless Loop Prevention

EthoVision XT prevents the occurrence of an endless loop in the Trial Control, which would make EthoVision XT unresponsive. When in a Sub-rule Reference box the number of repeats is not set to a fixed value and the Sub-rule has a 0-second duration, this Sub-rule is evaluated endlessly from the Sub-rule Reference box. To prevent this, in EthoVision XT a Sub-rule is evaluated only once per sample from the Reference box.

Sub-rules that are empty, only contain a Trial Control variable Action box, or Hardware Action boxes, are 0-second Sub-rules. With a 0-second Sub-rule, the Sub-rule Reference box never becomes inactive and, therefore, the Stop track Action box and Rule End box are never reached. In this case, the trial is stopped when you click the Stop Trial button (for live and offline tracking) or when the end of the video file is reached (for offline tracking).

Sub-Rule Start Conditions

To access these options, click Add in the sub-rule's Reference window.

Without Delay

Choose this option to start the sub-rule as soon as the sub-rule reference becomes active.

Clock Time

Choose this option to start the sub-rule at specific times of the day.

• Select Trial Day: Select the day from the start of the trial that the sub-rule should start. 1st trial day = the same day that the trial starts.
• Set Time (hh:mm:ss): Enter the time of the day that the sub-rule should start.

Example: If you want to start the sub-rule at 12:00 h of the fifth day of the trial, select 5th day and enter 12:00:00.

Delay

Choose this option to start the sub-rule with a specific delay from the moment that the Reference box becomes active.

Example: If you want to start the sub-rule one hour after the start of tracking, enter 01:00:00. Place the Reference box immediately to the right of the Start track box.

The time that the Reference becomes active is essentially the time that the previous box in the sequence becomes inactive (a condition being met, or an action being taken).

Trial Control Variable

Choose this option to start the sub-rule when a Trial Control variable gets a certain value for the first time since the Reference becomes active.

1. Click the Edit TC-Variable button. The TC-variable condition window appears.
2. From the first list, select the Trial Control variable. If you need to create a new variable, click TC Variables.
3. Select the comparison operator (=, >, etc.) from the second list.
4. Do one of the following:
   • If you want to compare the Trial Control variable with another variable, select that variable from the third list.
   • If you want to compare the Trial Control variable with a numerical value, enter this value in the third list.
   • If you want to compare a Trial Control variable with a formula, click the double-arrow button and select the operator, then the variable and/or values to complete the formula.

Example: You have defined the variable Phase which can have one of three values 1, 2, and 3 during the trial. You want to start a sub-rule when the current value of Phase is 2. Select Phase = 2.

Source: EthoVision XT 18 - THC - Trial and Hardware Control, Noldus Information Technology