For the purpose of embedded control systems, one of the following processor
technology is frequently used.

Programmable logical controller (PLC)—The programmable logical controller
is a specialized industrial controller. PLC is a device working in a real time: the
inputs from switches and sensors are processed on the basis of a logical program
and the output controller states change to steer machine or process. PLC may work
under heavy operating conditions (dust, electrical interferences, vibration, and shock).
These controllers can be used to implement sufficiently complicated control laws.

Microcontroller unit (MCU)—In essence, this is a small computer which constitutes
of processor, memory, and periphery on a single chip. The components of
most MCU are: processor, buses (address bus, data bus, and control bus), interruption
controller, DMA (direct memory access) controller, ROM memory, RAM
memory, timers, inputs, and outputs. Usually, MCU have ADC, digital outputs, digital
inputs, PWM outputs. Due to the comparatively low microcontroller prices, they
are widely used in mass production.