Mitsubishi MELSEC System Q Manual page 73

An Introduction to Programming
Function Block Diagram
All instructions are implemented using blocks, which are connected with one another with hori-
zontal and vertical connecting elements. There are no power bars.
Example for Function Block Diagram:
Sequential Function Chart
Sequential Function Chart (SFC) is a structured language which allows clear representation of
complex processes.
Sequential Function Chart has two basic elements, Steps and Transitions. A sequence con-
sists of a series of steps, each step separated from the next by a transition. Only one step in the
sequence can be active at any one time. The next step is not activated before the previous step
has been completed and the transition is satisfied.
MELSEC System Q Beginners Manual
Programming Languages
4 – 9