I want to derive the signal from a programmable I/O to turn a signal LED on/off for visual state indication. If the Output is programmed as "Output" it will produce a sink connection to the IC and produce a HIGH at the output. If it is configured as "Input" I need that it produces a HIGH signal regardless if the input has been wired to read in sink or source mode. For example, a LOW on the input should produce a HIGH on the output (the wiring is sourcing). A HIGH on the input should also produce a HIGH on the output (the wiring is sinking). I may have to use a selector for the input read state because basically it depends on the type of wiring of the connected sensor, so I may need to select if it is sink/source so the IC can deisplay appropriately.
Does anyone know how a PLC produces the indicator LED signal regardless of its wiring? It's pretty much the same operation here. Let me know if the PLC manufacturers use a different way to produce the indicator lights (hardware) or if they use microcontroller signals to produce the status indication (sfw).