Instrumentation Controls Lab (EE2327L) Practice Exam

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• During PID tuning, what characteristics of the system response are typically observed after applying a step input?
• How can you identify a process's dead time and time constant from a step test?
• Which of the following is not a primary process variable?
• What is the role of the reference pin in an instrumentation amplifier?
• Which of the following best distinguishes on-off control from PID control in terms of output behavior?
• What does a PID controller combine?
• Single-point grounding reduces ground loops in measurement systems. Which statement best describes this practice?
• In a first-order process with a dead time, what does the time constant τ represent?
• How would you assess sensor linearity within a lab measurement setup?
• In sensor signal conditioning, a Wheatstone bridge converts small resistance changes into a voltage. The bridge output is zero when the ratio R1/R2 equals the ratio R3/Rx.
• How does an isolation amplifier protect instrumentation systems?
• Define open-loop and closed-loop control in the context of instrumentation labs.
• Write the standard first-order plus dead-time (FOPDT) model form and identify its parameters.
• :Which line describes signal conditioning input that provides pulses to measure capacitance and convert to DC voltage?
• In ladder diagrams, which element is represented by a relay coil symbol and controls an external output device?
• What is the role of proportional control in a PID controller with respect to steady-state error and response speed?
• What part of a ladder diagram is shown at the start of each rung to describe the logic being executed?
• What is the difference between millivolt and volt signal levels, and what are the design implications?
• What is hysteresis in sensors and how does it affect measurement accuracy?
• Why is a bridge-type sensor commonly used for pressure measurement?
• How are Kp, L, and tau typically estimated from a step-response for PID tuning?
• What is an instrumentation amplifier and why is high input impedance important for sensor signals?
• What abbreviation represents the International Society of Automation?
• A 12-bit ADC is used with 0-5 V input. What is the least-significant-bit (LSB) value, and what is the maximum quantization error as a percentage of full scale?
• Which device in the output stage acts as a power amplifier?
• What minimum CMRR in dB is required to keep common-mode error below the signal when Vcm = 1 V and Vdiff = 10 mV?
• If you sample at a rate exactly at twice the highest frequency component, what is the expected outcome regarding aliasing?
• In the time-domain PID equation u(t) = Kp e(t) + Ki ∫ e dt + Kd de/dt, which term corresponds to the derivative action?
• What indicates control loop number?
• Which term in a PID controller helps reduce overshoot and dampen oscillations?
• Which device is used to measure pressure?
• Rise time for a first-order system is approximately 2.2 times the time constant.
• Describe a typical calibration procedure for a differential pressure transducer.
• What is differential measurement, and why is it used in sensor interfaces?
• Which output signal conditioning element ensures that the voltage applied to downstream components remains within safe limits?
• In ladder diagrams, what do rungs connect?
• Which control scheme uses sequential controllers?
• In Ziegler-Nichols tuning, which two measured values are used to compute the PID gains?
• Which pair of coil operations are used to implement memory in ladder logic?
• In a Wheatstone bridge-based sensor, what type of voltage is typically produced as the measurable signal?
• What is the purpose of a low-pass filter when measuring a sensor signal with high-frequency noise?
• How is overshoot quantified in a step response?
• Which abbreviation is used for Temperature Sensor/Primary Element?
• Which principle underlies a differential pressure flow meter and how does density affect the computed flow?
• What does cold-junction compensation do in thermocouple measurements?
• What is the purpose of an error budget during calibration?
• Calibration drift is best described as which of the following?
• What is input impedance in an instrumentation amplifier, and why is a high input impedance desirable?
• Briefly describe the Ziegler-Nichols tuning method for a PID controller and a typical outcome.
• Which abbreviation stands for Temperature Valve?
• Which abbreviation is used for Flow Transmitter?
• What is the effect of a deadband in a valve actuator on control performance?
• What is the settling time in a control system?
• Which symbol is used for Temperature Sensor/Primary Element?
• In ladder diagrams, the rails represent what in a relay logic circuit?
• Define resolution, sampling rate, and signal-to-noise ratio in the context of a DAQ system.
• During calibration of a differential pressure transducer, which step improves accuracy across temperature?
• Which programming language is used to program a PLC and is described as ladder-like with rails and rungs?
• In a DAC, what does INL (integral nonlinearity) describe?
• Which coil type is energized when the signal does not reach the coil and de-energized when it does reach the coil?
• In a step-test procedure to identify a first-order plus dead-time model, which parameters define G(s) ≈ K e^{-Ls}/(τ s + 1)?
• Which controller action uses the accumulated past errors over time to eliminate steady-state error, but can cause wind-up and slow response?
• Which abbreviation is used for Temperature Valve?
• What happens if the proportional gain is increased too much in a feedback controller?
• Which statement best describes the Cohen-Coon tuning method?
• Ladder Diagram horizontal lines of control logic are called what?
• What is a typical outcome of the Ziegler-Nichols tuning method?
• Which coil type is energized when the input signal does not reach the coil, and is de-energized when the input does reach the coil?
• What device is described as a microprocessor-based controller with programmable memory used to control equipment and processes?
• Which output signal conditioning element uses pulse width modulation to modify the voltage level?
• Which signal conditioning element uses PWM to adjust the voltage level?
• Why is the derivative term in a PID controller often filtered, and what is the trade-off?
• Describe a sensor calibration curve and outline steps to calibrate a temperature sensor (RTD/thermocouple) in the lab.
• In a unity feedback system, which term primarily eliminates steady-state error?
• Which practices help reduce noise in a lab measurement setup?
• Which controller type responds to the rate of change of the error to reduce overshoot and damp oscillations?
• Why is a four-wire (Kelvin) resistance measurement used?
• Which practice is effective for mitigating ground-loop noise in instrumentation loops?
• Which controller action is proportional to the magnitude of the current error and provides an immediate response, typically leaving a steady-state error when used alone?
• In process instrumentation, TT stands for?
• Flow sensor identification.
• In ladder logic, what is used with inputs and outputs to formulate the desired control operations?
• Which statement best describes a typical anti-windup strategy?
• Which statement about the 4-20 mA current loop is true?
• What are the standard components of a feedback control loop?
• Which list constitutes primary process variables?
• What is the role of a filter in a signal conditioning block, and how do you choose a cutoff frequency?
• For the first-order transfer function G(s) = K/(τs+1), what is the steady-state gain and what does τ represent?
• What is the purpose of shielded twisted-pair cables in sensor connections?
• What is the purpose of maintaining controlled impedance in a signal path?
• Indicators/generators are listed as part of which electronics category?
• There are two ______ in a ladder diagram drawn as vertical lines at the far ends of the page. In a relay logic circuit they would represent the active and zero volt connections of the power supply.
• In Level control, what are typical actuators?
• Which control strategy switches the control signal abruptly between two distinct limits and uses hysteresis to avoid chattering?
• Which line describes signal conditioning input that converts frequency of pulses to DC voltage?
• What is the purpose of an anti-aliasing filter in data acquisition, and what characteristics make it effective?
• Which statement best describes offset and gain error in sensor measurements?
• What is an anti-aliasing filter and why is it important before sampling a continuous signal with an ADC?
• What is the primary purpose of a PLC?
• What is the purpose of a transfer function and how do you obtain it from a step response?
• What is a common side effect of a large integral term if not properly tuned?
• A 4-20 mA signal is passed through a 250 Ω resistor. What voltage range is produced across the resistor, and what percentage of the ADC's input range does the 20 mA signal correspond to?
• Which abbreviation represents Temperature Indicating Controller?
• Which controller switches abruptly between two states with hysteresis to avoid high-frequency switching?
• Which term describes the memorized ON state that maintains an ON condition until a reset occurs?
• In diagnosing chattering, which action is appropriate?
• Define common-mode rejection ratio (CMRR) and explain its significance in differential sensing.
• Electric/Electronics for Processing Elements (Control Elements) is associated with which device?
• Which collection includes Non-Latching Coil, Inverse Non-Latching Coil, Set & Hold coil, and Reset coil?
• What is the basic procedure to calibrate a pressure transducer with a reference pressure source?
• In the categorization of automation topics, which category name encompasses Pneumatics/Hydraulics for Working Elements?
• What does P&ID stand for?
• In LabVIEW or similar software, what is a VI and how is it used in data acquisition?
• What statement best describes signal integrity and a technique to improve it in a lab setup?
• Which of the following is a disadvantage of a PLC?
• Which coil operation energizes once the signal reaches the coil and remains energized until the Reset Coil is activated (Memorized ON)?
• Which method is commonly used to reduce chattering related to actuator saturation and discretization?
• For Processing Elements (Control Elements), which item is listed as an example?
• What functions are typically included in signal conditioning for a sensor interface?
• Which term describes a signal conditioning element at the input that boosts the voltage to a level appropriate for the controller?
• Which statement about rungs is true?
• What is loop tuning in PID control, and what are manual tuning and Ziegler-Nichols methods?
• What is a strain gauge and how does its resistance change with deformation?
• Which acronym stands for International Society of Automation?
• Which term describes a signal conditioning element at the input that provides a DC voltage to the Wheatstone bridge and measures the differential voltage?
• Which statement describes the process reaction curve in the Cohen-Coon tuning method?
• Which coil operation energizes once the signal reaches the coil and remains de-energized until Set & Hold coil is activated (Memorized OFF)?
• How does temperature drift affect sensor readings and what are common mitigation strategies?
• Which of the following is NOT a recommended safety practice in instrumentation labs?
• Which controller type integrates the error over time to eliminate steady-state error?
• Which anti-windup method is described as bumpless transfer to ensure smooth controller handover during saturation?
• What components make up DAC output accuracy, and how would you assess it in the lab?
• In the FOPDT model, which parameter represents the time constant that characterizes the rate of process response after the initial delay?
• Which DAC error describes a constant voltage offset across all output codes?
• ANSI stands for what organization?
• Which option correctly identifies the control loop numbers?
• What is linearization in sensor signal processing?
• In temperature control, which components typically act as actuators?
• In the context of PID tuning, what is meant by robustness and how can it be improved?
• What device is commonly used in Electric/Electronics for Processing Elements (Control Elements)?
• Which term describes the memorized OFF state that maintains an OFF condition until a subsequent action?
• What does DNL (differential nonlinearity) measure in a DAC?
• What is dead time in a process control system and how does it affect stability and tuning?
• Define rise time for a step response and state its typical relationship to the time constant for a first-order system.
• Which items are listed for Electrics/Electronics for Input Elements?
• What is the significance of the sampling rate with respect to Nyquist criterion?
• During a step test for a FOPDT model, which value represents the dead time L?
• In ladder diagrams, which element is represented by NO/NC contact symbols and corresponds to physical hardware wired to PLC terminals?
• In Pneumatics/Hydraulics of Control Elements, which item is listed as an example?
• What is the typical role of a signal conditioner in a laboratory instrumentation chain?
• What is the purpose of a calibration checklist for laboratory instrumentation?
• What is the standard form of a first-order plus dead-time model?
• In instrumentation amplifiers, what does high CMRR help to achieve?
• During calibration of a pressure transducer, what data are recorded at each reference pressure point?
• What is a zero-crossing detector and in what applications is it commonly used?
• In the FOPDT model, which parameter represents the time delay before the process begins to respond?
• What is the purpose of signal conditioning in a measurement chain?
• Pneumatics/Hydraulics for Input Elements uses which items as standard?
• Which category would include Factory Automation and Food Manufacturing?
• Which statement correctly describes common implementations of cold-junction compensation?
• What is an error budget in instrument calibration?
• For equal-percent valves, which approach helps address nonlinearity in a control loop?
• In Pneumatics/Hydraulics for Control Elements, which item is listed?
• What describes the input, output and logic expression memory addressing structure of the PLC, with tag names used to describe addresses?
• Which transfer function corresponds to the continuous-time PID controller for E(s) given U(s)/E(s) = Kp E(s) + Ki/s E(s) + Kd s E(s)?
• Ladder Diagram vertical lines at the start and end of each rung are called what?
• Which abbreviation corresponds to the International Organization for Standardization?
• What is a typical PID-tuning lab sequence to achieve a desired closed-loop response?
• Pneumatics/Hydraulics for Processing Elements (Control Elements) lists which items?
• Why might you apply temperature compensation during pressure transducer calibration?
• Which of the following best describes the ultimate gain in the Ziegler-Nichols method?
• What best describes process control?
• What is sensor nonlinearity vs random noise?
• What best describes sampling jitter in measurement systems?
• What is the fundamental operating principle of a thermocouple, and how does it compare to an RTD?
• What does uncertainty analysis quantify, and what are common components of measurement uncertainty?
• Which statement best describes the purpose of impedance matching between a sensor and a data acquisition input?
• Why is handling outliers important in instrumentation experiments, and what is a recommended approach?
• Which pair of sensors is commonly used to measure temperature?
• Which statement best describes the gains Kp, Ki, and Kd?
• Which statement best describes the output of a Wheatstone bridge used with a strain gauge in one arm?
• In a measurement system, which statement best describes the relationship between resolution and quantization error?
• Which item is listed as an example of Electric Electronics of Working Elements?
• In LabVIEW-based data acquisition, what is the purpose of a scan engine and how does it relate to sampling rate?
• If differential pressure flow measurement assumes constant density but density varies, what should be done?
• Describe the 4-20 mA current loop used for transmitting sensor signals, including how the loop encodes the measurement and the role of supply voltage.
• Which of the following statements differentiates an ADC from a DAC and identifies a typical use in instrumentation labs?
• What is derivative kick and how can it be mitigated in PID implementations?
• In a Wheatstone bridge pressure sensor, what describes the electrical signal produced as pressure changes?
• Which controller action is directly proportional to the rate of change of the error and helps reduce overshoot and damp oscillations, but is sensitive to noise?
• In a typical sensor-signal chain, what is the recommended order of stages from sensor to ADC?
• Describe how a Wheatstone bridge is used to measure small changes in resistance from a strain gauge.
• Explain the concept of dynamic range in DAQ systems and why it matters.
• Which practice promotes safety when performing high-voltage instrumentation experiments?
• For Level measurement, which sensors are used?
• Which term refers to external devices that are turned on and off by a PLC, such as a motor or valve?
• Which of the following describes common noise sources in instrumentation loops and typical mitigation strategies?
• In process control, cascade control uses an inner loop to control a subordinate variable that sets the outer loop. Which term best describes this arrangement?
• Which term describes a signal conditioning element at the input that provides a small current to obtain a DC voltage?
• Which output signal conditioning element acts as a power amplifier?
• What is the purpose of a setpoint in process control?
• Describe a basic calibration procedure for a PT100 RTD using a four-wire method.
• Name a common anti-windup technique used with PID controllers and describe its basic principle.
• What is a common anti-windup technique in a discrete-time PID control loop?
• Pneumatics/Hydraulics for Input Elements includes which items?
• Why are short cables and proper shielding important in a measurement setup?
• What is the integral term in a PID controller, and how does it affect steady-state error?
• Why is impedance matching important when connecting sensors to data acquisition hardware?
• The horizontal lines connect the rails to the logic expressions. Each ______ is numbered in ascending sequential order.
• Which coil type energizes when the input signal reaches the coil and de-energizes when the input does not reach the coil?
• What term is defined as a state or fact of being in sequence, that is, a series of things following in order?
• How is the plant output typically represented for control design in the lab?
• Why is a thermistor very sensitive to temperature changes at low ranges and how does this affect linearization?
• Which of the following factors is considered when selecting PLCs?
• What is the primary purpose of an instrumentation amplifier in sensor signal conditioning?
• What distinguishes a linear valve from an equal-percent valve and how does it affect control loop design?
• Explain the difference between bias and offset in sensor readings and how you would correct them.
• Which of the following is an advantage of a PLC?
• Name two common anti-windup strategies used in PID control.
• According to the Nyquist criterion, what is the minimum sampling rate required to accurately sample a signal with a maximum frequency component of 3 kHz?
• Which acronym stands for an international standards body focused on automation and controls?
• What is common-mode rejection ratio (CMRR) and why is it important in instrumentation amplifiers?
• External actions such as push buttons and limit switches are called what?
• What is the derivative term in a PID controller, and what is its practical effect on the control signal?
• Compared to thermistors, RTDs have which characteristic?
• What is integral windup and why is it a concern in PID controllers?
• Piping and Instrumentation Diagrams are useful across which project stages?
• Which abbreviation represents Flow Valve?
• What is a typical step in calibrating a temperature sensor (RTD/thermocouple) in the lab?
• Which of the following is a common method for selecting PID gains during tuning?
• A calibration curve for a temperature sensor is created by:
• What is a deadband in a valve actuator?
• What are the two standard states of ladder diagram contacts indicating whether circuits are closed?
• What is the total number of distinct output codes produced by a 12-bit ADC?
• Which category includes Power Conductors, Power Transistors, and Power Thyristors?
• Which statement best describes the role of an ADC in a lab measurement chain?
• Which statement best defines signal conditioning in a measurement chain?
• Which control scheme uses multiple controllers acting on the same manipulated variable?
• Define process gain Kp in a FOPDT model and explain how it influences closed-loop response.