The Guide To PNP and NPN Wiring for Source and Sink Controllers

Sourcing and Sinking for I/O Modules and Sensors

Installing and troubleshooting control systems involves a lot of wiring. Even though many modern control systems rely on wireless communication devices, there will always be electrical connections between I/O devices and controllers. In many facilities and industries, the documentation for the system has been lost or is difficult to interpret. Electrical system diagnosis is among the most challenging maintenance tasks, often left up to those with the most experience.

If you find yourself facing this common situation of electrical troubleshooting but have few resources at your disposal, it helps to understand how and why the devices are chosen and connected.

This eBook will discuss the control system modules (considering both PLC and distributed I/O) and the polarity of the sensors and output devices that interface with the control systems.