for example, I am going to use a PLC to monitor a convection oven. I will use an output from the oven (wired in sink, not N-Synq) with a 12 V power supply from the oven as an input to the PLC. Other inputs will be proximity sensors and fault signals, the outputs will be buzzers, pneumatic valves, led's etc. Is there a website that can show me some of the fundamentals such as sink vs. source wiring etc??