Online and debug viewing of SFCs

Control Studio provides both an online and a debug view of a Sequential Function Chart (SFC) algorithm to help you with the development and use of SFCs for process control. Some of the functions you can perform in the online view include the following:

• disabling steps, transitions, and individual step actions

• forcing a transition to TRUE

• stopping, starting, and resetting embedded and linked composite levels of the algorithm

• stopping and starting execution of an SFC

• setting or forcing inputs to desired values. Control Studio only writes out those values that have been changed.

CAUTION!

If you edit an SFC online, you can affect the process that is currently running.

Double-click a transition to drill down into it and Control Studio's online view displays a graphical representation of the expression in a new dialog as follows:

• All components of a transition that have correctly evaluated are marked with a green check mark.

• Any parameters of the expression that have an error are marked with a question mark (?).

• Any element of the transition that has not correctly evaluated is marked with a red X.

• An expression that has not entirely been evaluated is marked with a red X while some of the underlying components (those that have evaluated correctly) display a green check mark.

• The expression contains a discrete parameter with a value of 0 is shown with a green checkmark in the lowest level of the tree next to the parameter name. A red X is displayed when the discrete parameter has any nonzero value.

The debug view for SFCs allows you to disable transitions, steps, and actions, as well as force transitions. When actions or steps are disabled, they are displayed as inactive in the diagram even though the active parameter still gives an indication of active; this way, you can see which actions would be taking place without actually executing the actions.