Mechatronics Engineering Lecture 10

Mechatronics Engineering (OFRME200) Lecture 10

• Course level: 2
• Semester: Fall
• Instructor: Walaa Shoeib
• University: Menoufia University, Faculty of Electronic Engineering

Chapter 5: Microcontroller Structure

• The lecture covers the structure of microcontrollers.

Registers

• Instruction Register (IR): Stores an instruction after fetching it from memory. The CPU places the instruction in the IR, which can then be decoded and used to execute an operation.

• Program Counter (PC): A special register that keeps track of the memory address of the next instruction to be executed in a program.

• Memory Unit: Contains the program counter (PC) , instruction register (IR), memory address register, and accumulator register.

• Control Unit (CU): Coordinates the operations of the other components.

• Arithmetic and Logic Unit (ALU): Performs arithmetic and logical operations.

• Data Bus: Carries data between the components.

• Address Bus: Carries memory addresses.

• Control Bus: Carries control signals.

Memory

• The memory unit stores binary data.

• The data in memory can be program instructions or numbers being operated on.

• The memory size is determined by the number of wires in the address bus.

• Individual memory cells are capable of storing either a 0 or a 1 bit

• Groups of cells form locations that hold words.

• Each location is identified by a unique memory address.

Types of Memory

• ROM (Read-Only Memory): Stores data permanently programmed during manufacture; data cannot be written to ROM.

• PROM (Programmable ROM): Can be programmed once.

• EPROM (Erasable Programmable ROM): Can be programmed and erased using ultraviolet light.

• EEPROM (Electrically Erasable Programmable ROM): Can be programmed and erased electrically.

• RAM (Random Access Memory): Stores data temporarily and is used for data currently being processed; data in RAM is lost when the power is turned off.

Open Loop Control System

• Output is determined only by the input without feedback.
• Control effect is determined without information about the value of the controlled variable.
• Instructions issued by a control device influence the actuator to change the object's state.
• Changes are not fed back to adjust further actions.
• Advantages: simple, cost-effective.
• Disadvantages: cannot adjust actual outputs.

Closed Loop Control System

• Also known as feedback control system.
• Includes a forward signal path and a feedback path.
• Sensors (ex: speed detector, position detector) detect actual displacement to be compared with the command value in a differential control system; high positioning accuracy, ensures accurate performance.
• Setting is more complex and expensive.

Component of Mechatronics System

Here are the key components of a mechatronics system:

• Actuators: (e.g., solenoids, DC motors, stepper motors, servo motors, hydraulics, pneumatics)
• Mechanics and Energy Converter: (e.g., mechanical, hydraulic, thermal, electrical)
• Sensors: (e.g., switches, potentiometers, photoelectrics, digital encoders, strain gauges, thermocouples, accelerometers, MEMS)
• Input Signal Conditioning and Interfacing: (e.g., discrete circuits, amplifiers, filters, A/D and D/A converters)
• Output Signal Conditioning and Interfacing: (e.g., amplifiers, D/A and A/D converters, PWM power transistors, power op-amps)
• Graphical Displays: (e.g., LEDs, digital displays, LCD, CRT)
• Digital Control Architectures: (e.g., logic circuits, microcontrollers, PLCs, sequencing, timing, logic and arithmetic control algorithms, communication)

This lecture focuses on the structure of microcontrollers, detailing key components such as the Instruction Register, Program Counter, and Control Unit. Students will explore how these elements interact to execute instructions within a microcontroller system. Ideal for second-year Mechatronics Engineering students.