What does an analog output module do in a PLC system?

• A. Converts digital data to a proportional voltage or current to control an analog field device.
• B. Reads input sensors.
• C. Stores ladder logic.
• D. Performs password authentication.

Answer: (A)

Converting the PLC’s digital command into a continuous signal that an analog field device can use is what an analog output module does. The PLC CPU computes a numerical value representing the desired level, and the analog output module translates that value into a proportional voltage or current (like 0-10 V or 4-20 mA) to drive devices such as a valve positioner, motor speed controller, or other analog actuators. This allows precise, variable control of processes rather than simple on/off action.

An analog input module is what reads sensors and brings their variable signals into the PLC, so that the program can react. Storing ladder logic is a function of the PLC’s memory, not the I/O hardware. Password authentication is a security feature and not related to producing or sending output signals.