PLC I/O Wiring Fundamentals
Digital and analog I/O wiring, sinking vs sourcing, shielded cables, and grounding best practices.
Digital I/O
Sourcing outputs (PNP) source current; sinking (NPN) sink current. Match to load type. Use proper fusing; group commons for easy troubleshooting.
Analog Signals
4–20mA preferred for noise immunity. Use twisted-pair shielded cable. Connect shield at one end (controller). Isolate from power cables.
Grounding
Star-point grounding at main cabinet. Separate analog and digital grounds. PE for safety; 0V for signal reference.
Related products
- 6ES7214-1AG40– S7-1200 CPU
- 6ES7223-1BL22– S7-1200 digital I/O
