Question

What is the function of PLC's output module?

• A. To read input signals from sensors
• B. To send output signals to actuators
• C. To store data from the industrial processes
• D. To execute the control program

Hint:

Remember the flow: Sensors $\rightarrow$ Input Module $\rightarrow$ CPU $\rightarrow$ Output Module $\rightarrow$ Actuators. The output module is the "Voice" of the PLC telling the machine what to do.

Answer 1

The Correct Option is B

1. Role of the Output Module: After the PLC's Central Processing Unit (CPU) finishes executing the logic program, it determines what actions need to be taken. The

output module receives these low-power digital commands from the CPU and converts them into signals that can drive industrial equipment.

2. Driving Actuators: The primary function is to

send output signals to actuators. Actuators are devices that do physical work, such as:

• Turning on electric motors.

• Opening or closing solenoid valves.

• Lighting up pilot lamps or sounding alarms.

• Energizing heating elements.

3. Isolation and Protection: In addition to signal conversion, output modules provide electrical isolation (often via opto-isolators) to protect the sensitive PLC processor from high-voltage spikes or electrical noise generated by the heavy industrial loads. While the "Input Module" reads sensors and the "CPU" executes the program, the "Output Module" is specifically responsible for commanding the actuators.