History of AutomationHistory of Automation1) Manual Control 2) Pneumatic Control 3) Hard wired logic Control4) Electronic Control using Logic Gates5) Programmable Logic ControllerI) Manual ControlAll the actions related to process control are taken by the operators Drawbacks1) Likely human errors and consequently its effect on quality of final product2) The production, safety, energy consumption and usage of raw material are all subject to the correctness and accuracy of human action.II) Pneumatic Control1) Industrial automation, with its machine and process control, had its origin in the 1920s with the advent of "Pneumatic Controllers". 2) Actions were controlled by a simple manipulation of pneumatic valves, which in turn were controlled by relays and switches. Drawbacks1.Bulky and Complex System2.Involves lot of rework to implement control logic3.Longer project timeIII) Hard wired logic control1.The contactor and Relays together with hardware timers and counters were used in achieving the desired level of automation Drawbacks1.Bulky panels2.Complex wiring3.Longer project time4.Difficult maintenance and troubleshootingIV) Electronic Control using Logic Gates1.In 1960s with the advent of electronics, the logic gates started replacing the relays and auxiliary contactors in the control circuits. 2.The hardware timers & counters were replaced by electronic timersAdvantages1.Reduced space requirements2.Energy saving3.Less maintenance & greater reliability Drawbacks1.Changes in control logic not possible2.More project timeV) Programmable Logic Controllers(PLC’s)1.In 1970s with the coming of microprocessors and associated peripheral chips, the whole process of control and automation underwent a radical change. 2.Instead of achieving the desired control or automation through physical wiring of control devices, in PLC it is achieved through a program or say software.

 automation The use of automatic machinery and systems, particularly those manufacturing or data-processing systems which require little or no human intervention in their normal operation. During the 19th century a number of machines such as looms and lathes became increasingly self-regulating. At the same time transfer-machines were developed, whereby a series of machine-tools, each doing one operation automatically, became linked in a continuous production line by pneumatic or hydraulic devices transferring components from one operation to the next. In addition to these technological

advances in automation, the theory of ‘scientific management’, which was based on the early time-and-motion studies of Frederick Winslow Taylor in Philadelphia, USA, in the 1880s was designed by Taylor to enhance the efficiency and productivity of workers and machines. In the early 20th century, with the development of electrical devices and time-switches, more processes became automatically controlled, and a number of basic industries such as oil-refining, chemicals, and food-processing were increasingly automated. The development of computers after World War II enabled more sophisticated automation to be used in manufacturing industries, for example iron and steel.The most familiar example of a highly automated system is perhaps an assembly plant for automobiles or other complex products. Over the last few decades automation has evolved from the comparatively straightforward mechanization of tasks traditionally carried out by hand, through the introduction of complex automatic control systems, to the widespread automation of information collection and processing.