Student: Gorea Vlad MariusGrupa: XM 31

TSAA Tema 2

Q1 - Consider the following as systems and indicate the input and output from each when considered as an entity:(a) a calculator,(b)a lowdspeaker,(c)a radio.

Answer - INPUT OUTPUT(a)-calculator- Pressure on keys, display of calculated value,.(b)-lowdspeaker- electrical signal, sound©-radio- radio signals, sound

Q2 - Explain the difference between open- and closed-loop control system.Answer -Open-loopIn an open-loop control system the output from the system has no effect on the input signal to the plant or processes.The output is determined solely by the initial setting.Open-loop system have the advantage of being relatively simple and consequently cheap with generally good reliability.However,they are often inaccurate since there is no correction for errors in the output which might result from extraneous disturbancesClosed-loopIn a closed-loop control system a signal indicating the state of the output of the system is fed back to the input where it is compared with what was required and the difference used to modify the output of the system so that it maintains the output at the required value.The term closed-loop refers to the loop created by the feedback path.Closed-loop system have the advantage of being relatively accurate in matching the actual to the required values..They are,however,more complex and so more costly with a greater chance of breackdown as a consequence of the greater number of components.And a comparation between Open- and Closed- loop is:Open- no feedback, closed- feedback

Q3 - Identify the basic functional elements that might be used in the closed-loop control system involved to:-A temperature-controlled water bath-A speed-controlled electric motor

Answer-(a) - Measurement- temperature sensor, controller- thermostat, correction- heater, process - water bath(b)- Measurement- rotary speed sensor, controller- motor, process- shaft

Q4 - Draw a black diagram of a domestic central heating system which has the following elements: Answer-(a),(b),(c),(d)