DVP- ES2/ EX2/ SS2/ SA2/ SX2/ SE&TP O pe r a t i on Ma nua l - Pr ogr am m i ng5- 10Other Points to Note:1. The instruction used for transferring the step (SET S□ or OUT S□) are suggested to beexecuted after all the relevant outputs and actions in the current step are completed.The execution results by the PLC are the same. However, if there are many conditions oractions in S10, it is recommended to modify the diagram in the left into the diagram in the right,which executes SET S20 after all actions are completed. The sequence will be moreunderstandable and clear with this modification.SETY0S10SS20S Y2S20Y1 SETY0S10SS20S Y2S20Y12. As indicated in the below diagram, make sure to connect RET instruction directly after the steppoint rather than the NO or NC contact.S0S20SRETX1S0S20SRETX15.4 Points to Note for Designing a Step Ladder Program1. The first step in the SFC is called the “initial step", S0 ~ S9. Use the initial step as the start of asequence and ends with RET instruction.2. If no STL instruction is in use, step point S can be used as a general-purpose auxiliary relay..3. When STL instruction is in use, the No. of step S cannot be repeated.4. Types of sequences: Single sequence: Only one simple sequence without alternative divergence, alternativeconvergence, simultaneous divergence or simultaneous convergence in the program. Complicated single sequence: Only one sequence with alternative divergence, alternativeconvergence, simultaneous divergence and simultaneous convergence in the program. Multiple sequences: More than one sequence in a program, maximum 10 sequences, S0 ~S9.
