1 Basic Principles of PLC Ladder Diagram Block: A block is a series or parallel operation composed of more than 2 devices. There are series block and parallel block. Series block Parallel block Separation line and combination line: The vertical line is used for separating the devices. For the devices on the left, the vertical line is a combination line, indicating that there are at least 2 rows of circuits on the left connected with the vertical line. For the devices on the right, the vertical line is a separation line, indicating that there are at least 2 rows of circuits interconnected on the right side of the vertical line).
1 2 Combination line for block 1 Separation line for block 2 Combination line for block 2 DVP-PLC Application Manual 1-7 Structure Explanation Instruction Devices Used Multiple output MPS MRD MPP - Coil driven output instruction OUT Y, M, S S Step ladder STL S Basic instruction Application instruction Application instructions See Ch.3 for basic instructions (RST/SET and CNT/TMR) and Ch.5 ~ 10 for application instructions Inverse logic INV -