Design for Engineering Unit 4: Instrumentation and Control Systems Definition of terms relating to instrumentation and control systems Digital Describes a method of storing, processing and transmitting information through the use of distinct electronic or optical pulses that represent the binary digits 0 and 1. Digital transmission/switching technologies employ a sequence of discrete, distinct pulses to represent information, as opposed to the continuously variable analog signal. DS-0, DS-1, Analogue Information in a continuously variable form. A useful illustration is to think of analogue information as being represented by an infinite number of shades of grey, rather than being represented by just pure black or pure white. Sound recorded on a vinyl record, for example, is analogue in nature. Traditional telephone and television technology is also analogue technology. Binary A numbering system using the digits "0" and "1" in the decimal system. An example of this is all computer programs are executed in binary form. Microprocessor A circuit of transistors and other electrical components on a chip that can process programs, remember information, or perform calculations. An example is the central processing unit on computers. Fuzzy Logic A conclusion reached by a computer recognizing that all values are not absolutes such as yes or no, black or white etc. Fuzzy logic makes calculations considering values in varying degrees between absolutes. For example, a computer might recognize black and white as absolutes, yet make an evaluation based on a shade of grey, which is somewhere between. Neural Systems A neural system consists of a set of highly interconnected entities, called nodes or units. Each unit is designed to mimic its biological counterpart, the neuron. Each accepts a weighted set of inputs and responds with an output. Examples include speech synthesis, diagnostic problems, medicine, business and finance, robotic control, signal processing, computer vision and many other problems that fall under the category of pattern recognition. Sensors An electronic device used to measure a physical quantity such as temperature, pressure or loudness and convert it into an electronic signal of some kind. An example is that in many solar heating systems there are sensors. These systems sensors measure freeze temps, outside temps, Water temps, Solar Panel Temps, and several other factors. Actuators Actuators are devices that make changes to the environment in response to signals. Actuators can be classified according to the power that makes them work electrical, pneumatic or hydraulic. Examples are motors, in one form or another, used in a remote control toy. Stepper motor A device that translates electrical pulses into precise mechanical movement. An example is a motor used to drive the gears which turn the hands in a quartz analog watch. Synchro motor The synchro drive system is a two motor, three/four wheeled drive configuration where one motor rotates all wheels to produce motion and the other motor turns all wheels to change direction. Open-loop control A control system which does not take any account of the error between the desired and actual values of the controlled variables. A characteristic of the open-loop controller is that it does not use feedback to determine if its input has achieved the desired goal. This means that the system does not observe the output of the processes that it is controlling. A typical example would be a conventional washing machine, for which the length of machine wash time is entirely dependent on the judgement and estimation of the human operator. Closed-loop control Systems that utilize feedback are called closed-loop control systems. The feedback is used to make decisions about changes to the control signal that drives a device. An example is if feedback indicates that the temperature in your home is below your desired set point, the thermostat will turn the heater on until the room is at least that temperature. Instrumentation Devices or instructions installed or inserted into hardware or software to monitor the operation of a system or component. An example of this is using a voltage meter to see how much amperage is coming from an electrical device. Sources http://www.calculator.org/OrderESD.html www.teladesign.com www.wgcu.org/watch/hdtv_glossaryofterms.html www.pbs.org/transistor/glossary.html www.scotsmist.co.uk/glossary_f.html http://uhavax.hartford.edu/compsci/neural-networks-tutorial.html www.qsconcepts.itcstore.com/default.aspx http://www.skillbank.co.uk/unnwebpage/actuators.htm www.seanet.com http://groups.csail.mit.edu/drl/courses/cs54-2001s/synchro.html http://en.wikipedia.org/wiki/Open_loop http://www.netrino.com/Publications/Glossary/PID.html Standards Standard #2: Students will develop an understanding of the core concepts of technology Benchmarks Y. The stability of a technological system is influenced by all of the components in the system, especially those in the feedback loop. DD. Quality control is a planned process to ensure that a product, service, or system meets established criteria. FF. Complex systems have many layers of controls and feedback loops to provide information. Standard #3: Students will develop an understanding of the relationships among technologies and the connections between technology and other fields of study. Benchmarks H. Technological innovation often results when ideas, knowledge, or skills are shared within a technology, among technologies, or across other fields. J. Technological progress promotes the advancement of science and mathematics. Standard #17: Students will develop an understanding of and be able to select and use information and communication technologies. Benchmarks M. Information and communication systems allow information to be transferred from human to human, human to machine, machine to human, and machine to machine. O. Communication systems are made up of source, encoder, transmitter, receiver, decoder, storage, retrieval, and destination. P. There are many ways to communicate information, such as graphic and electronic means. Q. Technological knowledge and processes are communicated using symbols, measurement, conventions, icons, graphic images, and languages that incorporate a variety of visual, auditory, and tactile stimuli.