A(n) ___ is a solid-state control device that is programmed and reprogrammed automatically to control an industrial process or machine.

A(n) ___ is a solid-state control device that is programmed and reprogrammed automatically to control an industrial process or machine.

• A. SCR
• B. PLC
• C. PNP
• D. SSR

Answer: (B)

A programmable logic controller is a solid-state device designed to automate and control industrial processes or machines by executing software that can be programmed and reprogrammed as needs change. It sits between sensors and actuators, reading input signals, processing them with logic, timers, and sequencing, and then sending appropriate output signals to control motors, valves, and other devices. This flexibility to change the control logic without rewiring makes it ideal for automatic control in dynamic industrial environments. In contrast, an SCR is a single thyristor used as a switch—for power control—not a programmable controller. A solid-state relay performs switching of a load using semiconductor devices but does not run a program to control a process. A PNP transistor is a type of semiconductor switch in a circuit, not a standalone controller capable of automatic, programmable process control.

A programmable logic controller is a solid-state device designed to automate and control industrial processes or machines by executing software that can be programmed and reprogrammed as needs change. It sits between sensors and actuators, reading input signals, processing them with logic, timers, and sequencing, and then sending appropriate output signals to control motors, valves, and other devices. This flexibility to change the control logic without rewiring makes it ideal for automatic control in dynamic industrial environments.

In contrast, an SCR is a single thyristor used as a switch—for power control—not a programmable controller. A solid-state relay performs switching of a load using semiconductor devices but does not run a program to control a process. A PNP transistor is a type of semiconductor switch in a circuit, not a standalone controller capable of automatic, programmable process control.