20MEC71- MECHATRONICS AND IOT

�Syllabus�

Unit - I Automation and Mechanical Measurements

Automation: Automation in Production System - Principles and Strategies of Automation - Basic Elements of an Automated System - Advanced Automation Functions - Levels of Automations. Mechanical

Measurements: Measurement of Displacement - Velocity - Force - Strain - Temperature - Pressure - Flow - Sound.

Unit – II Control System

Control System: Open Loop and Closed Loop Control - Block Diagrams - Transfer Functions - Laplace Transforms - Mathematical Model of Physical System – Proportional Integral (PI) and Proportional Integral Derivative (PID) Controllers.

Unit – III Microprocessor and Its Interfacing

Microprocessor and Its Interfacing: Organization of 8085 – Addressing Modes – Instruction Set – Simple Programs involving Logical - Branch/Call - Sorting - Evaluating Arithmetic Expressions and String Manipulation Instructions - A/D and D/A Converters.

Unit – IV Programmable Logic Controller

Programmable Logic Controller (PLC): Introduction - Architecture of PLC – I/O Modules – Distributed I/O Modules – Programming of PLC - Conversion of Relay Logic to Ladder Logic Programming - Math Instructions - Logical Instructions - Timer and Counter – Selection of PLC – Maintenance and Trouble Shooting of PLC.

Unit – V Introduction to IoT

Introduction to IoT: Defining IoT, Characteristics of IoT, Physical design of IoT, Logical design of IoT, Functional blocks of IoT, Communication models & APIs. Machine to Machine, Difference between IoT and M2M, Software define Network.

What is Industrial Automation?

• Industrial automation is the use of various control devices like PC’s/PLC’s/DCS, used to have control on various operations of an industry without significant intervention from humans and to provide automatic control performance.
• In industries, control strategies use a set of technologies which are implemented to get the desired performance or output, making the automation system most essential for industries.
• Industrial automation involves usage of advanced control strategies like cascade controls, modern control hardware devices as PLC’s, sensors and other instruments for sensing the control variables, signal conditioning equipments to connect the signals to the control devices, drives and other significant final control devices, standalone computing systems, communication systems, alarming and HMI (Human Machine Interface) systems.

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Need for Automation

Need for Industrial Automation...?

• To resolve the automation and control issues, industries use the ever changing technologies in control systems for efficient production or manufacturing processes.
• These requires the high quality and reliable control systems.
• New trends in industrial automation deals with latest control devices and communication protocols to control field devices like control valves and other final control elements.
• Some of the smart devices or instruments used in automated industry has the ability to control the processes and also communication capabilities without interfacing to other field level control devices like PLC’s.

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Industrial Automation net outcome

To reduce Periodic or Manual checking

• Critical applications periodic checking is necessary to perform  industrial operations. Automation reduces the periodic or manual operations and establishes the automatic working conditions.

To increase the Productivity

• Automation increases the production rate by producing output at greater amounts for a given labour input

Reduce the Production Cost

• Using the automatic machines and equipments, human intervention to control the processes abruptly falls. This reduces the investment on labour cost hence the production cost.

Cond.,

To improve Product Quality

• Continuously doing the same work may not be perfect in terms of quality specifications with human efforts. With automation equipment ,one can get reliable and uniform product quality by using  real time hardware control devices.

To increase the Flexibility

• Using the automation equipment various , process are handled simply without getting any complex environment particularly in manufacturing processes.

Operator Friendly and Improves the Safety

• Complexity of operating the equipment's or processes is reduced with  industrial automation. It changes the position of the operator as operator to the supervisory role.

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Automated Industrial setup

Industrial robot

Roller conveyor

Automation in Production system

• Automation can be defined as a technology concerned with the application of mechanical, electronic and computer based systems to operate and control production.
• Elements of automated production system can be separated into two categories:
• automation of the manufacturing systems in the factory
• computerization of the manufacturing support systems.

• In modern production systems, the two categories overlap to some extent, because the automated manufacturing systems operating on the factory floor are themselves often implemented by computer systems and connected to the computerized manufacturing support systems and management information system operating at the plant and enterprise levels.

Contd...

Opportunities of automation and computerization in a production system

• The term computer integrated manufacturing is used to indicate this extensive use of computers in production systems.

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Principles and Strategies of Automation

1. Specialization of operations: Special purpose equipment designed to perform one operation with the greatest efficiency. This is analogous to the concept of labour specializations and to improve labour productivity.
2. Combined operations:
1. Production occurs as sequence of operations. Complex parts may require dozens, or even hundreds, of processing steps.
2. The combined operations involves reducing the number of distinct production machines or workstations through which the part must be routed.
3. This is accomplished by performing more than one operation at a given machine, thereby reducing the number of separate machines needed.
4. Since each machine typically involves a setup, setup time can be saved as a consequence of this strategy. Material handling effort and non-operation time are also reduced.

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3. Simultaneous operations

• A logical extension of the combined operations strategy is to simultaneously perform the operations that are combined at one workstation. In effect, two or more processing (or assembly) operations are being performed simultaneously on the same work part, thus reducing total processing time.

4. Integration of operations

• Another strategy is to link several workstations together into a single integrated mechanism, using automated work handling devices to transfer parts between stations. In effect, this reduces the number of separate machines through which the product must be scheduled.

5. Increased flexibility

• This strategy attempts to achieve maximum utilization of equipment for job shop and medium volume situations by using the same equipment for a variety of parts or products. It involves the use of the flexible automation concepts.

6. Improved material handling and storage

• A great opportunity for reducing non productive time exists in the use of automated material handling and storage systems.

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7. On-line inspection

• Inspection for quality of work is traditionally performed after the process is completed. This means that any poor quality product has already been produced by the time it is inspected. Incorporating inspection into the manufacturing process permits corrections to the process as the product is being made.

8. Process control and optimization

• This includes a wide range of control schemes intended to operate the individual processes and associated equipment more efficiently. By this strategy, the individual process times can be reduced and product quality improved.

9. Plant operations control

• Whereas the previous strategy was concerned with the control of the individual manufacturing process, this strategy is concerned with control at the plant level. It attempts to manage and coordinate the aggregate operations in the plant more efficiently.

10. Computer-integrated manufacturing (CIM)

• Taking the previous strategy one level higher, we have the integration of factory operations with engineering design and the business functions of the firm.

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Automated Manufacturing systems

• Perform operations such as processing, assembly, inspection, or material handling, in some cases accomplishing more than one of these operations in the same system.
• They called automated because they perform their operations with a reduced level of human participation compared with the corresponding manual process.
• Some highly automated systems, there is virtually no human participation.
• Automated machine tools that process parts transfer lines that perform a series of machining operations
• Automated assembly systems
• Manufacturing systems that use industrial robots to perform processing or assembly operations
• Automatic material handling and storage systems to integrate manufacturing operations
• Automatic inspection systems for quality control

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Industrial Automation - Types�

• Automated manufacturing systems are classified into four basic types ,based on the flexibility and level of integration in manufacturing processes.
• Fixed Automation
• Programmable Automation
• Flexible Automation
• Integrated Automation

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Fixed Automation

• In this sequence of operations to be performed are fixed by the equipment configuration.
• It is used in high volume production with dedicated equipment.
• Examples of this automation system are automated assembly lines, distilled process, machine transfer lines.

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Programmable Automation

• In this, sequence of operations can be changed by changing the program.
• Sequence of operations is varied based on the different product configurations.
• Also new programs can be entered into the programmable devices for the new products.
• This type of system is used in batch processes, steel rolling mills, industrial robots, etc.

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Flexible Automation

• It is the extension for the programmable automation. This offers a greater flexibility to deal with product design variations.
• Operators can give commands in the form of codes in the computer program if wants to change the sequence of the process.
• Lower level equipments receive the instructions to operate at the field level without losing the production time.
• This type of automation is used in manufacturing multipurpose CNC machines, automatic guided vehicles, etc.

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Integrated Automation

• In this type total system is fully automated under computer control.
• Starting from designing process to the dispatching, whole system is completely automated.
• Even the equipment is handled by the robots.
• This system is used in computer integrated manufacturing systems.

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Automation Equipments�

Automated industry - Equipments

Basic elements of an Automated system

3 basic elements are there...

• Actuator

- Controlled by controller

• Controller

- Tells the actuator to do work

• Sensor

- Provides the feedback to the controller , so that it knows the actuator is performing the work.

Sensors and Actuators

• A sensor senses the various process variables and converts them into the electrical or optical signals. These sensors include temperature, pressure, velocity, flow, etc.
• Actuators convert the electrical signals to the mechanical means to gain control over processes. These include the relays, magnets, servomotors, etc.
• Some of the sensors and actuators have the capability to communicate with the industrial field communication buses which comes under the smart devices.

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Industrial computers

• Programmable Logic controllers (PLC’s) also called as industrial computers are capable of being programmed to perform certain control functions. It consists of a CPU or processor, I/O modules (both analog and digital) to connect the various input/output devices and relay modules. These may be modular which is of fixed type or integrated types to extend modules based on the inputs available.
• Along with the PLC’s, conventional PC’s are used to control the process by online or by changing the programs. PLC’s comes with dedicated software to program the control strategy.

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HMI(Human Machine Interface)

• HMI’s offers the facilities like, displaying the information on computer screens and other displays, logging the results in the database, giving alarm signal, etc.
• It uses technologies like SCADA (Supervisory Control and Data Acquisition) and other visual based technologies.

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Communication system

• In industries many sensors, actuators, controlling PC’s and other control devices are geographically distributed and interacting with each other via several data buses. There are three types of buses used in the industrial automation i.e., factory bus, process bus, and the field bus.
• Field bus interacts between field instruments and the control devices while the process bus connects the supervising level computers to the control devices like PLC’s. Factory bus connects the higher level of the organization to the supervising level. Different protocols are used for the communications like RS-485, profibus, CAN control modbus,etc.

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Structure of Industrial Automation�

• Structure of the industrial automation explains various levels of operation. These includes...
• Sensor level,
• Automation control level (Unit, cell, process controls),
• Supervision level and
• Enterprise level.
• Pyramid structure indicates that, as you go up the tip , the information is aggregated and while coming down it is dissolved.
• This means that the detailed information for a particular variable at the bottom.
• Industrial automation doesn’t mean that all the levels are automated like enterprise level need not be automated.

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Automation Structure

Sensor level

• Sensor level is also called as process layer. It uses the sensors and actuators to get the values of the process variables in continuous or periodical manner.
• Process layer act as eyes and arms of the industrial processes.
• Some of these instruments include pneumatic instruments, smart instruments, etc.

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Automation control level

• Automation control level or control layer uses industrial control devices like PC’s/PLC’s/DCS, etc. This level utilizes the various embedded processors, PID algorithms to control the process.

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Automation layers

Supervising level

• Supervising level or SCADA layer gets lots of channel information and stores the data in the system database.
• It acquires data from various control devices and displays them on HMI’s (Human Machine Interface).
• It also gives alarm to indicate the levels of the process and control variables.
• It uses special software to get the data and communication protocols to interact with the field devices.

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• Enterprise level performs the tasks like scheduling, orders and sales, product planning, etc.

Enterprise level

ADVANCED AUTOMATION FUNCTIONS

• Safety monitoring
• Maintenance and repair diagnostics
• Error detection and recovery.

SAFETY MONITORING

• An automated system is often installed to perform a potentially dangerous operation that would otherwise be accomplished manually by human workers
• Two reasons for providing an automated system with a safety monitoring capability
• to protect human workers in the vicinity of the system and
• to protect the equipment associated with the system.

Maintenance and Repair Diagnostics

• Maintenance and repair diagnostics refers to the capabilities of an automated system to assist in the identification of the source of potential or actual malfunctions and failures of the system
• Status monitoring
• Failure diagnostics
• Recommendation of repair procedure

Status monitoring serves two important functions in machine diagnostics

- providing information for diagnosing a current failure

-providing data to predict a future malfunction or failure

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ERROR DETECTION AND RECOVERY

• Error detection and recovery consists of two steps:

- Error detection

- Error recovery.

• The error defection step uses the automated system's available sensor systems to determine when a deviation or malfunction has occurred, correctly interpret the sensor signal(s), and classify-the error.
• Possible errors can be classified into one of three general categories

-Random errors

-systematic errors,

aberrations

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SENSORS

• A device which provides a usable output in response to a specified measurement
• A sensor acquires a physical quantity and converts it into a signal
• A measuring device passes through two main stages while measuring a signal. First, the measurand is felt or sensed by the sensing element

TRANSDUCER

• A device which converts one form of energy to another
• When input is a physical quantity and output electrical → Transducer
• When input is electrical and output a physical quantity → Actuator

COMMONLY DETECTABLE PHENOMENA

• Biological –
• Motion, force, blood composition, blood pressure, temperature, flow rate, urine composition, excretion composition, ECG, breathing sound, pulse, x-ray image, ultrasonic image
• Chemical
• Organic compounds, inorganic compounds, concentration, heat transfer rate, temperature, pressure, flow rate, humidity
• Electric/Electronic
• Voltage, current, charge, passive circuit parameters, electric field, magnetic field, magnetic flux, electrical conductivity, permittivity, permeability, reluctance
• Thermofluid
• Flow rate, heat transfer rate, infrared waves, pressure, temperature, humidity, liquid
• level, density, viscosity, Reynolds number, thermal conductivity, heat transfer coefficient, Biot
• number, image
• Mechanical
• Force (effort including torque), motion (including position and deflection), optical image, other images (x-ray, acoustic, etc.), stress, strain, material properties (density, Young’s modulus, shear modulus, hardness, Poisson’s ratio)

COMMON CONVERSION METHODS

• Physical

–thermo-electric, thermo-elastic, thermo-magnetic, thermo-optic

–photo-electric, photo-elastic, photo-magnetic,

–electro-elastic, electro-magnetic

–magneto-electric

• Chemical

–chemical transport, physical transformation, electro-chemical

• Biological

–biological transformation, physical transformation

COMMONLY MEASURED QUANTITIES

PHYSICAL PRINCIPLES: EXAMPLES

• Amperes’s Law

– A current carrying conductor in a magnetic field experiences a force (e.g. galvanometer)

• Curie-Weiss Law

– There is a transition temperature at which ferromagnetic materials exhibit paramagnetic behavior

• Faraday’s Law of Induction

– A coil resist a change in magnetic field by generating an opposing Voltage/current (e.g. transformer)

• Photoconductive Effect

– When light strikes certain semiconductor materials, the resistance of the material decreases (e.g. photoresistor)

CHOOSING A SENSOR

NEED FOR SENSORS

• Sensors are pervasive. They are embedded in our bodies, automobiles, airplanes, cellular telephones, radios, chemical plants, industrial plants and countless other applications.
• Without the use of sensors, there would be no automation !!

– Imagine having to manually fill Poland Spring bottles

RATING PARAMETERS

• Sensitivity and sensitivity error
• Signal-to-noise ratio
• Dynamic range
• Resolution
• Offset or bias
• Linearity
• Zero drift, full-scale drift, and calibration drift (Stability)
• Useful frequency range
• Bandwidth
• Input and output impedances

MOTION TRANSDUCERS

1. Displacement (including position, distance, proximity, size, and gauge)

2. Velocity (rate of change of displacement)

3. Acceleration (rate of change of velocity)

4. Jerk (rate of change of acceleration)

DISPLACEMENT SENSORS

• Potentiometer
• Rotatory Potentiometers
• Optical Potentiometer
• Linear-Variable Differential Transformer (LVDT)
• Capacitive Sensors
• Optical Encoders

POTENTIOMETER�

• Potentiometer consist of a resistance element with a sliding contact which can be moved over a length of the element.
• Element can be used for linear or rotary displacement, displacement is converted into potential difference

Linear Variable Differential Transformer (LVDT)

• The LVDT is a position-to-electrical sensor whose output is proportional to the position of a movable magnetic core.
• The core moves linearly inside a transformer consisting of a center primary coil and two outer secondary coils wound on a cylindrical form.

CAPACITIVE TRANSDUCER

• A capacitor is formed by two plates, which can store an electric charge. The stored charge generates a potential difference between the plates and may be maintained using an external voltage.

OPTICAL ENCODER

• Encoder is a device that provides a digital output as the result of a linear or angular displacement.
• A beam of light passes through a slots in a disc and it is detected by a suitable light sensor, when a dis is rotated, pulse output is produced by a sensors with a number of pulses being proportional to angle through which disc rotates
• Types
• Incremental encoders
• Absolute encoders

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STRAIN GAUGE

• Strain gauge is a metal wire foil or semiconductor strip which is wafer like and can be struck onto the surfaces like a postage stamp.
• When subjected to strain by an applied load, its resistance changes, fractional change in resistance is proportional to the load applied.

Pressure Sensors

• Pressure sensors operate in one of three modes, absolute, gauge, or differential measurement.
• Absolute pressure is detected relative to 0 Pa, i.e. the static pressure of a vacuum. The sensor is designed with one port for the fluid to enter and exert pressure on the sensing element.

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• Gauge pressure sensors - Measures pressure relative to a reference pressure, which is usually the local atmospheric pressure. The sensor has two ports, allowing entry of the fluid at the reference pressure, and at the pressure to be measured

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• Differential pressure sensors - The reference pressure is the pressure experienced at a different point in the system, as determined by the system designer. The change in differential output is positive or negative, depending on which is greater. The magnitude of the change is proportional to the pressure difference between the two domains.

PRESSURE SENSORS

Temperature Detection Sensors - Resistance Temperature Detector (RTD)�

• A Resistance Temperature Detector (also known as a Resistance Thermometer or RTD) is an electronic device used to determine the temperature by measuring the resistance of an electrical wire.
• it has good linear characteristics over a wide range of temperatures
• In RTD devices; Copper, Nickel and Platinum are widely used metals. These three metals are having different resistance variations with respective to the temperature variations. That is called resistance-temperature characteristics.

Thermocouple

• The thermocouple working principle is based on the Seeback Effect. This effect states that when a closed circuit is formed by jointing two dissimilar metals at two junctions, and junctions are maintained at different temperatures then an electromotive force (e.m.f.) is induced in this closed circuit.

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