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# Ee372 final exam

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• 1. EE372 FinalExam PLEASE DOWNLOAD HERE1. In process control the desired value of a system is referred to asthe__________?A) Process variableB) Controlled variableC) The controllerD) The setpoint2. In process control, the term the “process”, whatever it may be, may also bereferred to as the ______________.A) ObjectiveB) GoalC) PlantD) Output3. The device that exerts a direct influence on the process is called the_____________.A) Final control elementB) Basic elementC) The controllerD) The output4. Control system objectives should include:A) The system should be stableB) The system should provide the best steady?state regulation.C) The system should provide the best transient regulationD) None of the aboveE) All of the above5. The response criterion that specifies that the amplitude of each peak of eachcyclic response be a quarter of the preceding peak is called_________.A) Half waveB) Full waveC) Quarter ?amplitudeD) None of the above
• 2. 6. The mathematical relationship between the input of a block and the output ofthat block is known as the __________ __________.A) Sine functionB) Log functionC) Transfer functionD) Algebraic function7. The equation below describes the response of a __________________ ordersystem.A) FirstB) SecondC) LastD) Harmonic8. The current through a RTD can cause the RTD to heat up. This factor isaccounted for by use of the ____________________.A) Plank’s constantB) Boltzman’s constantC) Hooke’s LawD) The dissipation constantE) None of the above9. Type J, T, K, E, S, and R are all thermocouple types. The letterdesignates_______________.A) the qualityB) the sensitivityC) the temperature rangeD) the corrosive specifications10. Since Thermocouple voltages are small, great care should be taken toprotect against electrical noise by_________________.A) ShieldingB) twisting the conductorsC) differential amplificationD) All of the aboveE) None of the above11. Strain gauges operate based on the change in ___________________ of ametal under stress.A) CapacitanceB) InductanceC) ResistanceD) Impedance12. The primary form of ____________ sensor is the accelerometer.
• 3. A) TemperatureB) SolarC) MotionD) ph13. Flow across an orifice plate varies proportionally with the ___________ of thedifferential pressure.A) SquareB) CubeC) Square rootD) Exponential14. A rotameter, a moving vane flow meter and a turbine flow meter all place________________ in the flow of the material.A) An obstructionB) An orificeC) A Piezoelectric crystalD) A Magnetic pickup15. Elements of final control are:_______________.A) Signal conversionB) ActuatorC) Final control elementD) None of the aboveE) All of the above16. A _________________ is required to condition the signal from a computer sothat it might interact with process control equipment.A) Stand by power sourceB) Crowbar circuitC) Analog to digital converterD) Digital to analog converter17. A simple device that can convert mechanical motion to pneumatic pressurelevels is the __________________.A) PumpB) GeneratorC) Nozzle?flapper systemD) Wheatstone bridge18. Control valve sizing is done by choosing the valve size with the appropriate___________________.A) Metallic characteristicsB) Valve flow coefficientC) FlangeD) Orifice plate19. A process that can be controlled by reading on or off conditions and
• 4. responding with other on or off conditions is called a _____________ statesystem.A) AnalogB) Continuous controlC) DiscreteD) PID20. Alarm conditions can best be described by_________________________.A) Loop equationsB) Simultaneous equationsC) Boolean equationsD) None of the above21. Programmable logic controllers can replace electromagnetic relays in controlsystems.A) TrueB) False22. The below schematic symbol is a _________________.A) Normally closed limit switchB) A normally open momentary pushbuttonC) A pressure switchD) A level switchE) A normally closed temperature switch23. Could the below circuit be used to control a motor starter? A) YesB) No24. The process the PLC uses to read the inputs, solve the ladder logic, anddrive the outputs is the PLC_____________ for that specific application.A) State tableB) MemoryC) Throughput timeD) Application25. In order for the PLC to interact with the process inputs and outputs the I?Omust be compatible with the input signal and output signal __________.A) CapacityB) Voltages and currentsC) Scan timeD) Memory
• 5. 26. Sensor resistance varies from 25 to 1.5 kΩ as a variable changes from cminto cmax. Design a signal-conditioning system that provides an output varyingfrom –2 to +2 V as the variable changes from min to max. Power dissipation inthe sensor must be kept below 2.5 mW.Solution:The circuit could be implemented as under:27. A 10-bit unipolar ADC with a reference of 5.00 F and a 44-μs conversion timewill be used to collect data on time constant measurement. Thus, the input will beof the form V (t) = 4(1− et/τ ) . What is the minimum value of τ for which reliabledata samples can be taken if no Sample-and-Hold circuit is used?Solution;28. A type K thermocouple with a 0°C reference will be used to measuretemperature between 200°C and 350°C . Devise a system that will convert thistemperature range into an 8-bit digital word with conversion from 00H to 01H at200°C and from FEH to FFH at 350°C . An ADC is available with a 2.500-Vinternal reference. At 200°C a type K TC produces 8.13 mV. At 350 °C a type KTC produces 14.29 mV.29. A strain gauge has a and a nominal resistance of 120 Ω . Calculate theresistance change resulting from a strain of 144μin / in .Solution:30. Consider the phototransistor with IV curves below left and used in the circuitbelow right. Calculate the output voltage when the light intensity is equal to 20 W/m2 .Solution:31. A 4- to 20-mA control signal is loaded by a 100-Ω resistor and must produce a20- to 40-V motor drive signal. Develop the equation relating the input current tothe output voltage. Implement the equation if a power amplifier is available thatcan output 0 to 100V and has a gain of 10.32. It is desired to control the batch below process with a programmable logiccontroller. All of the sensors and control devices are discrete devices operating at120 vac. List which signals are inputs and which are outputs. What is thecomplete I/O count that should be specified for the programmable logiccontroller? How would you recommend starting and stopping this system?
• 6. 33. Consider the drawing below and answer each of the following questions withone or more complete sentences:a. What kind of drawing is represented above?b. What is driving the setpoint for the pressure of ingredient “A”?c. What kind of signal is driving the setpoint for ingredient “A”?d. What is controlling the flow of ingredient “B”?e. What is driving the setpoint of the flow of product leaving at “C”?34. Consider the logic diagram below. Convert this logic diagram to ladder logic