The three ways to control a VFD from a PLC: discrete I/O, an analog speed signal, or a network. Wiring, drive settings and tips for each.
Current loops and voltage signals compared: noise immunity, cable length, wire-break detection, wiring and how to scale the value in a PLC.
What normally open and normally closed really mean, how to read the symbols, and when to choose NO or NC for switches, relays and sensors.
What sinking and sourcing mean for PLC inputs and outputs, how they pair with PNP and NPN devices, and how to read confusing manufacturer labels.
M12 4-pin, 5-pin and 8-pin pinouts with wire colors, what A, B, D, X, S, T and L coding mean, and how to choose the right cordset.
Step-by-step wiring for 2-wire and 3-wire proximity sensors, PNP and NPN outputs, and connecting them to a PLC, with troubleshooting tips.
PNP sensors switch the positive supply to the load; NPN sensors switch the load to 0V. Here is how to tell them apart, how to wire each, and which one your PLC needs.
