What is the typical voltage level used in most PLC control circuits?

The typical voltage level used in most PLC control circuits is 24V DC. This voltage is favored for several reasons. First, 24V DC is safe for personnel and minimizes the risk of electrical shock, which is an important consideration in industrial environments where operators are often in close proximity to the control systems.

Moreover, using 24V DC allows for easy integration with various field devices, such as sensors and actuators, which are commonly designed to operate at this voltage level. This helps in ensuring compatibility and simplifies wiring and installation processes across the control landscape.

Additionally, 24V DC power supplies are generally more reliable and efficient for control applications. They can maintain stable voltage even under varying load conditions, which is essential for the consistent performance of PLC systems.

In contrast, higher voltage levels like 120V AC and 220V AC are typically used for power distribution rather than direct control circuits. These voltages are not commonly used in PLC applications due to safety concerns and the need for additional isolation and protection mechanisms.