Ansa Iftikhar Ahmed Din 201202238 Introduction to Information Technology Control Systems

Overview control systems examples of control systems diagrams references air – conditioning system refrigeration central – heating system car manufacture

Control systems Control system is one that uses microprocessors or computers to control certain physical conditions, either keeping them the same over a period of time or varying them according to predefined values & lengths of time. The computer reviews the data from the sensors…if the values are outside the given parameters it takes action to try and get the values within acceptable ranges. It does that by sending signals to devices controlling the process.

air-conditioning system Air condition is a closed system of copper tubes in the form of coils containing a chemical liquid that can easily be converted to a gas & back to liquid again. One set of coils is outside the building (condensing unit) & the other (evaporating unit) is inside. The compressor compresses cool-low pressure gas into hot-high pressure gas.as the gas moves through the condenser outside the building, it cools down into liquid. This liquid flows through the piping & passes through an expansion valve, causing it to evaporate into a cold low-pressure gas. As the liquid changes to gas & evaporates, it absorbs heat from the inside of the building. This causes the room to cool down. The gas then continues to the compressor to continue the cycle

Diagram of air-conditioning system

refrigeration The refrigeration process works much the same as air conditioning. The condensing unit is at the rear of the refrigerator & the evaporating unit is inside the refrigerator The main inputs are a temp. sensor to monitor the temp. inside the refrigerator, a contact switch or pressure sensor for the door & a number pad or similar device to input the required temp. The microprocessor compares the data from the sensor with the pre-set value input by the user. If the temp. is higher than this value, the processor activates the compressor on. If it is not then the microprocessor turns the compressor off.

Diagram of refrigeration

Central heating system Most modern central heating systems use water as the medium to get heat from the central source ( the boiler) to all of the areas to be heated. The main parts of a central-heating system consist of a boiler, a hot-water cylinder, a pump and some radiators. The boiler is used to heat the water in the system, although, despite its name, it does not boil the water. The water from the boiler flows into a hot-water cylinder and the pump then causes the heated water from the cylinder to flow around the system to the radiators. The radiators are metal panels that are fixed to the wall in the rooms that need heating. In a microprocessor – controlled central heating system, users press the touch screen to select the temp. they want. The microprocessor reads the data from a temp. sensor on the wall & compares it with the value the user has requested. If it is lower, then the microprocessor switches the boiler & the pump on. If it is higher, the microprocessor switches both off.

Diagram of central heating system

Car manufacture Computer – controlled robots are used in various manufacturing industries, including the manufacture of cars. The computer controls the movement of the arm so that, using different end effectors, a variety of jobs can be carried out. End effectors are the devices attached to the end of the robot arm. A common one is a “gripper”.

(Cont.) Car manufacture The types of end effectors used in car manufacture are: Cameras to inspect Welding guns to weld parts of the car body together Grippers to pick up parts and place them somewhere else Screw drivers to place and screws, nuts, bolts and rivets Spray guns to paint the car body Sanders/polishers/finishers to produce a shiny finish after painting

(Cont.) Car manufacture Industrial robots are designed to perform exactly the same action over & over again. For example, as a car passes along the production line the robot arm tightens the nuts on the car wheels in exactly the same position and with exactly the same pressure.

(Cont.) Car manufacture A robot arm carries out the following tasks on a car production line: painting car bodies putting in car wheels drilling the holes in cars fixing rivets to car bodies tightening bolts inserting car engines

(Cont.) Car manufacture Robots are used rather than humans because: a robotic arm has greater accuracy than a human the running costs are lower compared with paying a person robotic arms do not get tired, so work is of a consistent standard the whole process can be continuous, without having to stop at shift changeovers

References Applied ICT Brian Sargent and Graham Brown https://www.google.com.sa/search?hl=en&biw=910&bih=365&site=imghp&tbm=isch&sa=1&q=car+manufacture+robot+arm&oq=car+manufacture+robot+arm&gs_l=img.3...9514.18535.0.18739.25.19.0.6.6.2.304.3096.7j2j8j1.18.0...0.0...1c.1.kkapFASx-jY https://www.google.com.sa/search?hl=en&biw=910&bih=365&site=imghp&tbm=isch&sa=1&q=central+heating+systems&oq=central+heati&gs_l=img.3.0.0l10.128490.131852.0.133397.14.13.0.0.0.0.319.1703.8j2j1j2.13.0...0.0...1c.1.euxZj5bnKhE Applied ICT Brian Sargent and Graham Brown

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