Which type of voltage supply is typically used in PLC systems?

In PLC (Programmable Logic Controller) systems, a low voltage DC supply, commonly around 24V, is typically used for several key reasons. This voltage level is generally considered safe for personnel working around the equipment and minimizes the risk of electrical shock. The 24V DC supply is compatible with a wide range of sensors and actuators, which are essential components of control systems, allowing for effective integration of different devices.

Additionally, most PLCs are designed to operate efficiently at this voltage level. This ensures they can reliably process inputs from field devices and control outputs to drive motors, solenoids, and other industrial components. The use of low voltage DC also supports stable operation under varying load conditions, which is crucial in industrial settings where PLCs often manage multiple processes.

Moreover, while high voltage AC supplies and medium voltage AC supplies are used in other industrial applications for powering heavy machinery and large systems, they are not suitable for the sensitive electronic components found in PLCs. Battery backup supplies, while important for maintaining system operation during power interruptions, are not the primary type of voltage supply for normal PLC functions. Thus, a low voltage DC supply is the standard for facilitating the effective functionality of PLC systems.