{"id":187,"date":"2018-11-06T09:46:39","date_gmt":"2018-11-06T09:46:39","guid":{"rendered":"http:\/\/tis-eg.com\/en\/?p=187"},"modified":"2018-11-06T09:46:39","modified_gmt":"2018-11-06T09:46:39","slug":"what-is-automation-mean","status":"publish","type":"post","link":"https:\/\/tis-eg.com\/en\/what-is-automation-mean\/","title":{"rendered":"what is Automation mean ?"},"content":{"rendered":"

what is Automation mean ?<\/b><\/p>\n

Automation<\/b>\u00a0is the technology by which a process or procedure is performed with minimum human assistance.<\/sup>Automation\u00a0<\/sup>\u00a0or automatic control is the use of various\u00a0control systems<\/a>\u00a0for operating equipment such as machinery, processes in factories, boilers and heat treating ovens, switching on telephone networks, steering and stabilization of ships, aircraft and other applications and vehicles with minimal or reduced human intervention. Some processes have been completely automated.<\/p>\n

Automation covers applications ranging from a household\u00a0thermostat<\/a>\u00a0controlling a boiler, to a large industrial control system with tens of thousands of input measurements and output control signals. In control complexity it can range from simple on-off control to multi-variable high level algorithms.<\/p>\n

In the simplest type of an automatic\u00a0control loop<\/a>, a\u00a0controller<\/a>\u00a0compares a measured value of a process with a desired set value, and processes the resulting error signal to change some input to the process, in such a way that the process stays at its set point despite disturbances. This closed-loop control is an application of negative feedback to a system. The mathematical basis of\u00a0control theory<\/a>\u00a0was begun in the 18th century, and advanced rapidly in the 20th.<\/p>\n

Automation has been achieved by various means including mechanical,\u00a0hydraulic<\/a>,\u00a0pneumatic<\/a>, electrical, electronic devices and\u00a0computers<\/a>, usually in combination. Complicated systems, such as modern factories,\u00a0airplanes<\/a>\u00a0and\u00a0ships<\/a>\u00a0typically use all these combined techniques. The benefit of automation include labor savings, savings in\u00a0electricity costs<\/a>, savings in material costs, and improvements to quality, accuracy and precision.<\/p>\n

The\u00a0World Bank<\/a>‘s\u00a0World Development Report<\/a>\u00a02019 shows evidence that while automation displaces workers, innovation creates new industries and jobs.<\/sup><\/p>\n

The term\u00a0automation<\/i>, inspired by the earlier word\u00a0automatic<\/i>\u00a0(coming from\u00a0automaton<\/a><\/i>), was not widely used before 1947, when Ford established an automation department.<\/sup>\u00a0It was during this time that industry was rapidly adopting\u00a0feedback controllers<\/a>, which were introduced in the 1930s.<\/sup><\/p>\n

Open-loop and closed-loop (feedback) control.<\/span><\/h2>\n

Fundamentally, there are two types of control loop; open loop control, and closed loop\u00a0feedback<\/a>\u00a0control.<\/p>\n

In open loop control, the control action from the controller is independent of the “process output” (or “controlled process variable”). A good example of this is a central heating boiler controlled only by a timer, so that heat is applied for a constant time, regardless of the temperature of the building. (The control action is the switching on\/off of the boiler. The process output is the building temperature).<\/p>\n

In closed loop control, the control action from the controller is dependent on the process output. In the case of the boiler analogy this would include a thermostat to monitor the building temperature, and thereby feed back a signal to ensure the controller maintains the building at the temperature set on the thermostat. A closed loop controller therefore has a feedback loop which ensures the controller exerts a control action to give a process output the same as the “Reference input” or “set point”. For this reason, closed loop controllers are also called feedback controllers.<\/sup><\/p>\n

The definition of a closed loop control system according to the British Standard Institution is ‘a control system possessing monitoring feedback, the deviation signal formed as a result of this feedback being used to control the action of a final control element in such a way as to tend to reduce the deviation to zero.’\u00a0<\/sup><\/p>\n

Likewise, a\u00a0Feedback Control System<\/i>\u00a0is a system which tends to maintain a prescribed relationship of one system variable to another by comparing functions of these variables and using the difference as a means of control The advanced type of automation that revolutionized manufacturing, aircraft, communications and other industries, is feedback control, which is usually\u00a0continuous<\/i>\u00a0and involves taking measurements using a\u00a0sensor<\/a>\u00a0and making calculated adjustments to keep the measured variable within a set range.\u00a0<\/sup>\u00a0The theoretical basis of closed loop automation is\u00a0control theory<\/a>.<\/p>\n

Control actions.<\/span><\/h2>\n
Main article:\u00a0Control system<\/a><\/div>\n

<\/span>Discrete control (on\/off)<\/span><\/h3>\n

One of the simplest types of control is\u00a0on-off<\/i>\u00a0control. An example is the thermostat used on household appliances which either opens or closes an electrical contact. (Thermostats were originally developed as true feedback-control mechanisms rather than the on-off common household appliance thermostat.)<\/p>\n

Sequence control, in which a programmed sequence of\u00a0discrete<\/i>\u00a0operations is performed, often based on system logic that involves system states. An elevator control system is an example of sequence control.<\/p>\n

PID controller.<\/span><\/h3>\n
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A\u00a0block diagram<\/a>\u00a0of a PID controller in a feedback loop, r(t<\/i>) is the desired process value or “set point”, and y(t<\/i>) is the measured process value.<\/div>\n<\/div>\n<\/div>\n

Main article:\u00a0PID Controller<\/a><\/div>\n

A\u00a0proportional\u2013integral\u2013derivative controller<\/b>\u00a0(PID controller<\/b>) is a\u00a0control loop<\/a>\u00a0feedback mechanism<\/a>\u00a0(controller<\/a>) widely used in\u00a0industrial control systems<\/a>.<\/p>\n

In a\u00a0PID loop<\/a>, the controller continuously calculates an\u00a0error value<\/i>\u00a0{display style e(t)}<\/span>\"e(t)\"<\/span>\u00a0as the difference between a desired\u00a0setpoint<\/a>\u00a0and a measured\u00a0process variable<\/a>\u00a0and applies a correction based on\u00a0proportional<\/a>,\u00a0integral<\/a>, and\u00a0derivative<\/a>\u00a0terms, respectively (sometimes denoted\u00a0P<\/i>,\u00a0I<\/i>, and\u00a0D<\/i>) which give their name to the controller type.<\/p>\n

The theoretical understanding and application dates from the 1920s, and they are implemented in nearly all analogue control systems; originally in mechanical controllers, and then using discrete electronics and latterly in industrial process computers.<\/p>\n

Sequential control and logical sequence or system state control.<\/span><\/h3>\n
Main article:\u00a0Programmable logic controller<\/a><\/div>\n

Sequential control may be either to a fixed sequence or to a logical one that will perform different actions depending on various system states. An example of an adjustable but otherwise fixed sequence is a timer on a lawn sprinkler.<\/p>\n\n\n\n\n
State Abstraction<\/th>\n<\/tr>\n
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This state diagram shows how\u00a0UML\u00a0<\/a>can be used for designing a door system that can only be opened and closed<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

States refer to the various conditions that can occur in a use or sequence scenario of the system. An example is an elevator, which uses logic based on the system state to perform certain actions in response to its state and operator input. For example, if the operator presses the floor n button, the system will respond depending on whether the elevator is stopped or moving, going up or down, or if the door is open or closed, and other conditions.<\/sup><\/p>\n

An early development of sequential control was\u00a0relay logic<\/a>, by which electrical relays engage electrical contacts which either start or interrupt power to a device. Relays were first used in telegraph networks before being developed for controlling other devices, such as when starting and stopping industrial-sized electric motors or opening and closing solenoid valves. Using relays for control purposes allowed event-driven control, where actions could be triggered out of sequence, in response to external events. These were more flexible in their response than the rigid single-sequence cam timers. More complicated examples involved maintaining safe sequences for devices such as swing bridge controls, where a lock bolt needed to be disengaged before the bridge could be moved, and the lock bolt could not be released until the safety gates had already been closed.<\/p>\n

The total number of relays, cam timers and drum sequencers can number into the hundreds or even thousands in some factories. Early\u00a0programming<\/a>\u00a0techniques and languages were needed to make such systems manageable, one of the first being\u00a0ladder logic<\/a>, where diagrams of the interconnected relays resembled the rungs of a ladder. Special computers called\u00a0programmable logic controllers<\/a>\u00a0were later designed to replace these collections of hardware with a single, more easily re-programmed unit.<\/p>\n

In a typical hard wired motor start and stop circuit (called a\u00a0control circuit<\/i>) a motor is started by pushing a “Start” or “Run” button that activates a pair of electrical relays. The “lock-in” relay locks in contacts that keep the control circuit energized when the push button is released. (The start button is a normally open contact and the stop button is normally closed contact.) Another relay energizes a switch that powers the device that throws the motor starter switch (three sets of contacts for three phase industrial power) in the main power circuit. Large motors use high voltage and experience high in-rush current, making speed important in making and breaking contact. This can be dangerous for personnel and property with manual switches. The “lock in” contacts in the start circuit and the main power contacts for the motor are held engaged by their respective electromagnets until a “stop” or “off” button is pressed, which de-energizes the lock in relay.[10]<\/a><\/sup><\/p>\n

Commonly\u00a0interlocks<\/a>\u00a0are added to a control circuit. Suppose that the motor in the example is powering machinery that has a critical need for lubrication. In this case an interlock could be added to insure that the oil pump is running before the motor starts. Timers, limit switches and electric eyes are other common elements in control circuits.<\/p>\n

Solenoid valves<\/a>\u00a0are widely used on compressed air or hydraulic fluid for powering\u00a0actuators<\/a>\u00a0on mechanical components. While motors are used to supply continuous rotary motion, actuators are typically a better choice for intermittently creating a limited range of movement for a mechanical component, such as moving various mechanical arms, opening or closing valves, raising heavy press rolls, applying pressure to presses.<\/p>\n

Computer control.<\/span><\/h3>\n

Computers can perform both sequential control and feedback control, and typically a single computer will do both in an industrial application.\u00a0Programmable logic controllers<\/a>\u00a0(PLCs) are a type of special purpose microprocessor that replaced many hardware components such as timers and drum sequencers used in\u00a0relay logic<\/a>\u00a0type systems. General purpose process control computers have increasingly replaced stand alone controllers, with a single computer able to perform the operations of hundreds of controllers. Process control computers can process data from a network of PLCs, instruments and controllers in order to implement typical (such as\u00a0PID<\/a>) control of many individual variables or, in some cases, to implement complex control\u00a0algorithms<\/a>\u00a0using multiple inputs and mathematical manipulations. They can also analyze data and create real time graphical displays for operators and run reports for operators, engineers and management.<\/p>\n

Control of an\u00a0automated teller machine<\/a>\u00a0(ATM) is an example of an interactive process in which a computer will perform a logic derived response to a user selection based on information retrieved from a networked database. The ATM process has similarities with other online transaction processes. The different logical responses are called\u00a0scenarios<\/i>. Such processes are typically designed with the aid of\u00a0use cases<\/a>\u00a0and\u00a0flowcharts<\/a>, which guide the writing of the software code.The earliest feedback control mechanism was the water clock invented by Greek engineer Ctesibius (285\u2013222 BC).<\/p>\n","protected":false},"excerpt":{"rendered":"

what is Automation mean ? Automation\u00a0is the technology by which a process or procedure is performed with minimum human assistance.Automation\u00a0\u00a0or automatic control is the use of various\u00a0control systems\u00a0for operating equipment such as machinery, processes in factories, boilers and heat treating ovens, switching on telephone networks, steering and stabilization of ships, aircraft and other applications and […]<\/p>\n","protected":false},"author":1,"featured_media":188,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18],"tags":[],"class_list":["post-187","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles"],"_links":{"self":[{"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/posts\/187","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/comments?post=187"}],"version-history":[{"count":1,"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/posts\/187\/revisions"}],"predecessor-version":[{"id":189,"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/posts\/187\/revisions\/189"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/media\/188"}],"wp:attachment":[{"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/media?parent=187"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/categories?post=187"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tis-eg.com\/en\/wp-json\/wp\/v2\/tags?post=187"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}