Which device is defined as a solid-state control device that is programmed and reprogrammed automatically to control an industrial process?

Which device is defined as a solid-state control device that is programmed and reprogrammed automatically to control an industrial process?

• A. PNP
• B. PLC
• C. SSR
• D. SCR

Answer: (B)

A programmable logic controller is a rugged solid-state control device designed to be programmed and reprogrammed automatically to manage an industrial process. It combines a processor with input/output interfaces, so it can read sensors, run user-defined logic, and send control signals to actuators. This setup lets the system adapt to different process requirements without rewiring, and it supports complex sequencing, timing, and interlocks essential for automation in manufacturing or processing environments. This description fits PLCs because the core feature is automatic reprogramming and control of a process. In contrast, a transistor-based PNP device is just a type of switch or amplifier, not a programmable controller. A solid-state relay acts as a switch controlled by logic signals but lacks built-in programming to manage a process. An SCR handles power control by triggering and latching on, but it doesn’t provide programmable logic or process automation.

A programmable logic controller is a rugged solid-state control device designed to be programmed and reprogrammed automatically to manage an industrial process. It combines a processor with input/output interfaces, so it can read sensors, run user-defined logic, and send control signals to actuators. This setup lets the system adapt to different process requirements without rewiring, and it supports complex sequencing, timing, and interlocks essential for automation in manufacturing or processing environments.

This description fits PLCs because the core feature is automatic reprogramming and control of a process. In contrast, a transistor-based PNP device is just a type of switch or amplifier, not a programmable controller. A solid-state relay acts as a switch controlled by logic signals but lacks built-in programming to manage a process. An SCR handles power control by triggering and latching on, but it doesn’t provide programmable logic or process automation.