What is a common type of input for a PLC?

Digital inputs, such as switches or sensors, are indeed a common type of input for a Programmable Logic Controller (PLC). These digital inputs typically represent two states: on or off, which corresponds to binary values of 1 or 0. They are commonly used in industrial automation to monitor the status of various field devices, such as limit switches, push buttons, or proximity sensors.

When these sensors detect a condition—like a switch being closed or an object being present—they send an electrical signal to the PLC, which can then process this information to make decisions or trigger outputs. This binary input is essential for creating various control logic based on physical processes, allowing the PLC to perform tasks such as starting a motor or activating a safety system.

In contrast, other options like analog outputs are about the control signals sent out by the PLC instead of the inputs it receives. Wireless communication signals can be a part of a PLC system but are not typically categorized as standard input types in the way that digital and analog inputs are. Process control variables typically refer to the actual measurements or conditions within the process and are not direct input types for the PLC itself.