Defining FlipFlop Variables

FlipFlop Variable Operating Principle

In Trending Tool, a FlipFlop variable is a memory which changes status according to condition-related events.

An Trending Tool FlipFlop variable is characterized by four attributes:

Reach 1	Reach 0
Starting event (mandatory)	Ending event (optional)
Starting condition (optional)	Ending condition (optional)

Definition of an event and of a condition:

An event is the combination between a boolean variable and a (rising or falling) edge.
A condition is a boolean equation.

Behavior of a FlipFlop variable:

It reaches 1 if the starting event has the expected edge and the starting condition is true.
It reaches 0 if the ending event has the expected edge and the ending condition is true.

Restriction:

A Trending Tool FlipFlop variable cannot directly or indirectly depend on itself.

Viewing the FlipFlop Variable Dialog Box

The New FlipFlop variable dialog box enables you to configure the parameters of a FlipFlop variable.

Dialog Box Controls	Description
Starting or Ending Event	Defining an event: the selected button enables you to choose a variable of the configuration. the and buttons indicate which edge (rising or falling) of the selected variable will generate events.
Starting Condition or Ending Condition	A condition is a calculated variable contained in the FlipFlop variable. Edit: this button enables you to create or change a condition. Delete: this button deletes the existing condition.
OK	This button confirms the changes made to the equation and closes the dialog box.
Cancel	This button closes the dialog box without applying the changes made to the variable's equation.

Creating a FlipFlop Variable

You can create FlipFlop variables at any time in Trending Tool, just like with any other variable, even during or after a recording.

To create a FlipFlop variable in a module, proceed as follows:

Step	Action
1	Display the module tree to select the module to which you wish to add a calculated variable.
2	Use the FlipFlop variable... command from the Insert menu. This command opens the new FlipFlop variable dialog box.
3	In the dialog box, select a starting event and an ending event (boolean variables).
4	Starting or ending conditions are optional as an empty condition is always true.

Changing a FlipFlop Variable

FlipFlop variables are boolean variables. They have the same display and analysis properties. The FlipFlop variable properties dialog box features an Equation tab.

To change the equation of a FlipFlop variable:

Step	Action
1	Select the variable you wish to change in the variable statistical table.
2	Use the Properties... command from the Edit menu. This command opens the dialog box displaying the properties of the FlipFlop variable.
3	Click on the Equation tab in the dialog box in order to change the current FlipFlop variable.
4	Click on the Change... button to open the equation editor.
5	Customize the FlipFlop variable as required and click on the OK button to save your changes and close the editor. The Cancel button enables you to cancel any changes and close the editor at the same time.
6	Click on the OK button to close the FlipFlop variable properties dialog box. The developments of the variable are immediately recalculated for the whole of the recording.

Deleting a Variable Linked To a FlipFlop Variable

The FlipFlop variables are linked to the variables acting in their events and conditions. If you try to delete such variables, Trending Tool will display an alert message preventing you from deleting them.