Features, Sfc | Delta DVP-ES2/EX2/SS2/SA2/SX2/SE manual

5 . Sequential Function Chart

action and the transition from one step to another generally requires some transition criteria (condition). The action of the previous step finishes as long as all criteria is true. When next step begins, the action of previous step will be cleared. The step-by-step transition process is the concept for designing sequential function chart (SFC).

Features:

1.Users do not have to consider the sequential relationship between outputs as general ladder logic because STL operation process can execute multiple outputs or interlocked outputs automatically. An easy sequential design between the steps is the only thing required to control the machines.

2.The actions in SFC are easy to understand. Also, it’s easy to do a trial operation, error detecting or period maintenance.

3.SFC functions as a flow chart. The STL operation works on the internal step relay S, which is also the step points representing each state in SFC. When current step is finished, the program proceeds to the next step according to the transition condition and the desired continuous control purpose can be achieved by this process.

4.Cycle process can be performed. Please refer to the SFC opposite. Initial step S0 transfers to general step S21 by transition condition X0. S21 transfers to S22 or jumps to S24 by the condition X1 and X2. The process finally proceeds to S25 then a single cycle process is completed when S25 returns to S0 with transition condition X6 fulfilled.