When specifying the behavior of real time control systems, it is important to be able to specify the time between events. We use Triggers to identify that specific events occur. Relative Time Criteria (RTC) are behavior specifications that specify a certain time relationship between two Trigger events in a TestCase.

You need two trigger events to specify an RTC. Triggers can be used in several RTCs. Before continuing with the samples below, you should add at least two Triggers to different output Signals.

RTC1

Relative Time Criteria are specified at the TestCase level.  To view the TestCase Properties dialog box:

1.Select TestCase‑>Properties from the main menu.

2.Click the Pass/Fail Criteria tab

3.Click the Relative Time Criteria tab.

TestCaseRelTimeCriteria

Use this form to specify an RTC:

1.Click the Add button to add an RTC.

Click to expand.

Click to expand.

2.Select the Trigger that is the Cause trigger.  This is the one that will occur first.

3.In the Cause panel, click the Set button.

4.Select the Trigger that is the Effect trigger.  This is the one that will occur second.

5.In the Effect panel, click the Set button.

6.Enter Time. This is the expected time between the Cause Trigger and the Effect Trigger.

7.Set the tolerances appropriately.

8.Click the OK button.

Click to expand.

Click to expand.

Notes:

The Relative Time Criteria test is a higher level test in the pass/fail algorithm hierarchy. If the basic pass/fail algorithm returns failure, then the RTC tests are not performed.

Even when Relative pass/fail criteria is used with triggers, the absolute time criteria still applies.

Related Topics:

Pass/Fail Judgment Overview

DataBlock Overview

TestCase Properties

TestCase Properties - Absolute Time Tolerances

TestCase Properties - Relative Time Criteria

Creating a Trigger (example)