Power Engineering - 4A Instrumentation Practice Questions with Verified Answers

Power Engineering - 4A Instrumentation Practice Questions with Verified Answers Common indicators necessary for proper process operation may include: a. low water cut-offs, flame scanners and safety values b. pressure, value position, and conductivity measurement devices c. interlocks and permissives d. programmable logic controls e. pneumatic, hydraulic, and electrical switches b. pressure, value position, and conductivity measurement devices A sensing element receives its signal from the: a. control valve b. controller c. recorder d. controlled variable e. transducer d. controlled variable The major elements needed to construct automatic control loop instrumentation systems includes a sensing element, a ___________, a controller and a control valve. a. recorder b. resistance c. float cage d. transmitter e. manometer d. transmitter A control loop controller: a. sends a signal to a primary element b. measures the manipulated variable value, eliminating the need of a primary element c. will always eliminate deviation d. constantly compares input signals to the set point e. does not require a set point value d. constantly compares input signals to the set point A process variable which is adjusted in order to maintain or achieve some desired value of another variable is termed the: a. final variable b. process variable c. controlled variable d. manipulated variable e. transmitting variable d. manipulated variable A sensing element sends its signal to the: a. transmitter b. controller c. transducer d. control valve e. recorder a. transmitter The coefficient of expansion of mercury is nearly linear for temperatures between: a. -45 and 485oC b. -30 and 425oC c. -39 and 450oC d. 75 and 450oC