Ladder Wiring Diagram. The programmable controller was designed to replace physically small control relays that make logic decisions but are not designed to handle heavy. The loads in a ladder diagram are always and shall be connected in parallel on the rungs.
Chapter 6 developing fundamental plc wiring diagrams and ladder logic programs electromagnetic control relays the plc s original purpose was the replacement of electromagnetic relays with a solid state switching system that could be programmed. Read the ladder diagram from left to right then up to down in order. A number on the right side of the rail references the contacts associated with the coil fig.
Line diagrams provide a fast easy understanding of the connections and use of components.
The loads in a ladder diagram are always and shall be connected in parallel on the rungs. The loads in a ladder diagram are always and shall be connected in parallel on the rungs. The programmable controller was designed to replace physically small control relays that make logic decisions but are not designed to handle heavy. The power flow is taken to be from the left hand vertical across a rung.
