Wait until the PLCsets the value of a specific tag to a “Running” status code.A chart could wait for a specific value on a tag, and then proceed after the value has met some set-point. In many cases, a chart will need to wait for some other system to finish with a task before moving on. This is similar to receiving a handshake from the PLC before moving on. Charts can freely read and interact with the rest of Ignition, so a step in a chart can read a tag, run a query, make a web services call, read a local file, or do anything that is possible from a Python script. When the second script finishes, the chart flows to the End step, and concludes the chart.In PCS7 you have CFC and SFC editor included. It works like a flow diagram and ONLY active step will be elaborate (every scan of plc too). Once the script finishes, the chart then flows to Start Motor 2, and calls a script that would start Motor 2. Itmeans all function are elaborate every scan of plc and output will be energized always.The Start Motor 1 action would then run a script to start Motor 1.The chart would Start and then move to the first motor.Sequential Function Chart Architecture Examples (3)When limit switch 2 finally operates, the carrier drive motor comes to a stop When limit switch 4 operates, the carrier is immediately retracted.
(2)When limit switch 2 operates due to the carrier being retracted, carrier movement is paused for five seconds, and (1)When the start push button is pressed, the carrier advances and is immediately retracted when limit switch 3 operates. (4)A dynamic monitor function does away with the need for an experienced engineer for problem solving. (3)Overall control content and operation is easy to understand. (This is automatically processed by the PLC.) (2)Circuits that contain interlock circuits or redundant output need not be designed. (1)Constantly changing sequences are expressed by process progression operation.