1 . PLC Conc e pts1- 71.5.9 ORB (Connect block in parallel)ORB instruction connects a block in parallel with another blockORB instruction1.5.10 MPS / MRD / MPP (Branch instructions)These instructions provide a method to create multiplexed output branches based on current resultstored by MPS instruction.BranchinstructionBranchSymbol DescriptionMPS ┬Start of branches. Stores current result ofprogram evaluation. Max. 8 MPS-MPP pairs canbe appliedMRD ├ Reads the stored current result from previousMPSMPP └ End of branches. Pops (reads then resets) thestored result in previous MPSNote: When compiling ladder diagram with WPLSoft, MPS, MRD and MPP could be automaticallyadded to the compiled results in instruction format. However, sometimes the branch instructionsare ignored by WPLSoft if not necessary. Users programming in instruction format can enter branchinstructions as required.Connection points of MPS, MRD and MPP:MPSMRDMPP MPPMPSNote: Ladder diagram editor in ISPSoft does not support MPS, MRD and MPP instructions. Toachieve the same results as branch instructions, users have to connect all branches to the lefthand bus bar.WPLSoft ISPSoft1.5.11 STL (Step Ladder Programming)STL programming uses step points, e.g. S0 S21, S22, which allow users to program in a clearerand understandable way as drawing a flow chart. The program will proceed to next step only if the
