SFC Steps

A step represents a stable state. It is drawn as a square box in the SFCClosed"Sequential function chart" It can be used to program processes that can be split into steps. The main components of SFC are: - Steps with associated actions - Transitions with associated logic conditions - Directed links between steps and transitions chart. Each step of a program is identified with a unique number. At runtimeClosedIn computer science, runtime (or run-time) describes the operation of a computer program, the duration of its execution, from beginning to termination (compare compile time). Within KAS, runtime also refers to the virtual machine that manage the program written in a computer language while it is running, a step can be either active or inactive according to the state of the program.


  • To change the number of a step, transition or jump, select it and hit Ctrl+ENTER keys.

All actions linked to the steps are executed according to the activity of the step.

Inactive step Active step

In conditions and actions of the SFC program, you can test the step activity by specifying its name ("GS" plus the step number) followed by ".X".
For example:

GS100.X

is TRUE if step 100 is active
(expression has the BOOL data type)

You can also test the activity time of a step, by specifying the step name followed by ".T". It is the time elapsed since the activation of the step. When the step is deactivated, this time remains unchanged. It will be reset to 0 on the next step activation. For example:

GS100.T

is the time elapsed since step 100 was activated
(expression has the TIME data type)

Initial steps

Initial steps represent the initial situation of the chart when the program is started. There must be at least one initial step in each SFC chart. An initial step is marked with a double line: