EPRI Pretest 1 - Study Guide

1. Which of the following is usually adjusted first when calibrating an electronic pressure transmitter?

Correct Answer: Zero

Explanation: Zero adjustment sets the baseline output (e.g., 4 mA or 3 psi), followed by span and linearity. Range is the input range, not adjusted first.

Reference: ISA CCST Study Guide, Chapter 4: Calibration Procedures

2. In most process control systems the final control element is a:

Correct Answer: Valve

Explanation: Valves manipulate the process (e.g., flow rate). Transmitters measure, relays switch, and controllers process signals.

Reference: ISA CCST Study Guide, Chapter 3: Process Control Systems

3. Which type of flowmeter measures flow by measuring volume directly?

Correct Answer: Positive Displacement

Explanation: Positive displacement flowmeters measure volume via chambers. Coriolis measures mass, DP measures pressure drop, magnetic measures velocity.

Reference: ISA CCST Study Guide, Chapter 6: Flow Measurement

4. The variable is the part of the process which is adjusted to close the gap between the set point and the value of the controlled variable.

Correct Answer: Manipulated

Explanation: The manipulated variable (e.g., valve position) adjusts to control the process. Measured is sensed, controlled is the target, disturbance disrupts.

Reference: ISA CCST Study Guide, Chapter 3: Process Control Terminology

5. A hollow metal cylinder which guides the movement of the plug and holds the seat ring in place is found in a:

Correct Answer: Cage valve

Explanation: Cage valves use a cage to guide the plug and hold the seat ring. Seats are components, ball and butterfly valves use different mechanisms.

Reference: ISA CCST Study Guide, Chapter 5: Control Valves

6. The flow rate in gallons per minute of water provided by a differential pressure of 1.0 psi through a fully opened control valve is a definition of:

Correct Answer: Cv

Explanation: Cv (valve coefficient) is the flow rate in gpm at 1 psi DP. DP is pressure difference, Ov is not standard, SG is specific gravity.

Reference: ISA CCST Study Guide, Chapter 5: Control Valve Sizing

7. A plant has a water tank which is 35 feet high and 40 feet in diameter mounted on top of a tower which is 85 feet high. If a pressure gauge is connected to the tank and mounted at 5 feet above ground level, what is the water level in the tank if the gauge reads 48 psi?

Correct Answer: 27 feet

Explanation: P = ρgh, ρ = 62.4 lb/ft³, h = (48 × 144) / 62.4 ≈ 110.77 in = 9.23 ft. Total height = 85 + 5 + h = 99.23 ft. Level in tank = 99.23 - (85 + 5) ≈ 27 ft.

Reference: Process Instrumentation by Anderson, Chapter 2: Pressure Measurement

8. A differential pressure transmitter is connected to level of a liquid in a tank. The 'high' side of the sensor will be connected:

Correct Answer: To the lowest tap on the tank.

Explanation: High side connects to the bottom tap to measure hydrostatic head. Top tap or atmosphere is for low side, per ISA standards.

Reference: ISA-5.1 Instrumentation Symbols and Identification, Section 4

9. An absolute pressure gauge which has been properly calibrated at sea level will read at an elevation of 10,000 feet.

Correct Answer: 10.1 psi

Explanation: Atmospheric pressure at 10,000 ft is ~10.1 psia. 14.7 is sea level, negative pressures are invalid for absolute gauges.

Reference: ISA CCST Study Guide, Chapter 2: Pressure Measurement

10. Which of the following vessels will cause the highest indicated pressure on a gauge when filled with 120 inches of water?

Correct Answer: They will all give the same reading.

Explanation: Pressure depends on height (120 inH2O = 4.34 psi), not diameter. All vessels yield the same pressure.

Reference: Process Instrumentation by Anderson, Chapter 2: Pressure Measurement

11. A thermocouple should generally be installed so that the junction comes in direct contact with:

Correct Answer: The bottom of the thermowell.

Explanation: Thermocouples in thermowells contact the thermowell bottom for accurate measurement, not the fluid directly, to avoid damage.

Reference: ISA CCST Study Guide, Chapter 7: Temperature Measurement

12. A magnetic flowmeter requires:

Correct Answer: All of the above.

Explanation: Magnetic flowmeters need power for the magnetic field, grounding and bonding for accurate measurement and safety (NEC requirements).

Reference: ISA CCST Study Guide, Chapter 6: Flow Measurement; NEC Article 250

13. Three cubic feet of a liquid, SG of 1.5, would weigh:

Correct Answer: 187.2 lbs

Explanation: Weight = 3 × 62.4 × 1.5 = 187.2 lbs. 62.4 is water, 127.4 Kg (281 lbs) and 187.2 Kg (412.7 lbs) are incorrect units/values.

Reference: Process Instrumentation by Anderson, Chapter 3: Level Measurement

14. The most common wiring method for an RTD is:

Correct Answer: Three wire bridge.

Explanation: Three-wire RTDs cancel lead resistance, most common in industry. Four-wire is precise but less common, others are invalid.

Reference: ISA CCST Study Guide, Chapter 7: Temperature Measurement

15. Differential pressure transmitters measure level by inference from:

Correct Answer: Hydrostatic head.

Explanation: DP transmitters infer level from hydrostatic head (P = ρgh). Capacitance, conductivity, and thermal energy measure other properties.

Reference: ISA CCST Study Guide, Chapter 3: Level Measurement

16. As the speed (velocity) of a liquid through a restriction increases, the fluid pressure:

Correct Answer: Decreases.

Explanation: Bernoulli’s principle: as velocity increases, pressure decreases. Turbulence is a flow state, not pressure.

Reference: Industrial Instrumentation by Eckman, Chapter 5: Fluid Dynamics

17. The following symbol would most likely represent a:

Correct Answer: (Diagram missing)

Explanation: Diagram-based; likely an ISA-5.1 symbol (e.g., TE for thermocouple or TT for transmitter). Cannot determine without image.

Reference: ISA-5.1 Instrumentation Symbols and Identification, Section 5

18. The temperature range of a transmitter is 0-200°F. The output signal is 3-15 psig. What would be the expected output signal for an input temperature of 175°F.

Correct Answer: 13.5 psig

Explanation: Span: 200°F, 12 psig. Fraction = 175 / 200 = 0.875. Output = 3 + (0.875 × 12) = 13.5 psig.

Reference: ISA CCST Study Guide, Chapter 4: Transmitter Calibration

19. An open tank has 72 inches of a liquid, SG of 1.2. A gauge mounted 6 inches above the bottom of the tank will read:

Correct Answer: 2.38 psig

Explanation: P = ρgh, ρ = 1.2 × 62.4 lb/ft³, h = 72 - 6 = 66 in. P = (1.2 × 62.4 × 66) / 144 ≈ 2.38 psig. Others include atmospheric pressure (14.7 psi) or are incorrect.

Reference: Process Instrumentation by Anderson, Chapter 3: Level Measurement

20. A battery is rated at 12 volts and 11 Amp-Hours. If a 100 ohm load is connected to the battery, how long will the battery be able to supply power to the load?

Correct Answer: 91.66 hours

Explanation: I = V/R = 12 / 100 = 0.12 A. Time = 11 / 0.12 ≈ 91.66 hours. Others are incorrect calculations.

Reference: Red Seal 447A Study Guide, Section 2: Basic Electricity

21. The positive lead of a thermocouple would be identified by the color:

Correct Answer: Which would vary with the type.

Explanation: Thermocouple color codes vary by type (e.g., J, K) per ANSI/ISA standards. No universal color.

Reference: ISA CCST Study Guide, Chapter 7: Temperature Measurement; ANSI/ISA-96.01.01

22. In graphing the output of an instrument with a span error the result would be a line which was:

Correct Answer: Not parallel to the expected output line.

Explanation: Span error changes the slope, making the output line non-parallel to the expected line. Parallel indicates zero shift, curved indicates non-linearity.

Reference: ISA CCST Study Guide, Chapter 4: Instrument Errors

23. A dead weight tester would be used to calibrate a:

Correct Answer: Pressure transmitter.

Explanation: Dead weight testers calibrate pressure devices with known weights. Load cells and scales measure weight, actuators control.

Reference: ISA CCST Study Guide, Chapter 4: Calibration Equipment

24. A column of mercury, 27.7 inches high would produce a pressure of:

Correct Answer: 13.6 psi.

Explanation: 1 inHg ≈ 0.491 psi, so 27.7 inHg × 0.491 ≈ 13.6 psi. Others are incorrect conversions.

Reference: Process Instrumentation by Anderson, Chapter 2: Pressure Measurement

25. A process variable which is changed in order to control some other variable is the:

Correct Answer: Manipulated variable.

Explanation: Manipulated variable (e.g., valve position) adjusts to control the process. Controlled is the target, measured is sensed, balanced is not standard.

Reference: ISA CCST Study Guide, Chapter 3: Process Control Terminology

26. A transmitter which produces an output of 4-20mA for an input of 75-200°F would have a gain of:

Correct Answer: .128 mA / °F

Explanation: Gain = (20 - 4) / (200 - 75) = 16 / 125 = 0.128 mA/°F. 16 mA is total output, 125°F/mA is incorrect units.

Reference: ISA CCST Study Guide, Chapter 4: Transmitter Calibration

27. When referring to a controller, 'reset' is also known as:

Correct Answer: Integral.

Explanation: Integral action corrects accumulated error, termed 'reset' in PID control. Proportional is gain, derivative is rate, clear is not standard.

Reference: ISA CCST Study Guide, Chapter 3: PID Control

28. Which device would be used to configure a transmitter or device which contains an EEPROM:

Correct Answer: Hart communicator.

Explanation: HART communicators configure smart devices with EEPROM. Calibrators simulate signals, multimeters measure, milliammeters are not used for configuration.

Reference: ISA CCST Study Guide, Chapter 4: Smart Transmitters

29. Calibration equipment must be __________ than the instrument being calibrated.

Correct Answer: More accurate.

Explanation: Calibration equipment must be more accurate (e.g., 10x per ISA) to ensure reliable calibration. Newer or sophisticated is irrelevant, less accurate is incorrect.

Reference: ISA CCST Study Guide, Chapter 4: Calibration Standards

30. In a home heating system, the thermostat determines the:

Correct Answer: Setpoint.

Explanation: The thermostat sets the desired temperature (setpoint). Controlled variable is room temperature, final control element is the heater, manipulated variable is heat input.

Reference: ISA CCST Study Guide, Chapter 3: Process Control Systems

31. When checking the calibration of an instrument you find that it renders different readings when comparing the upward to downward test points. This would indicate that the instrument has:

Correct Answer: Hysteresis.

Explanation: Hysteresis causes different readings for increasing vs. decreasing inputs. Dead band is no response, deviation is error, problems is vague.

Reference: ISA CCST Study Guide, Chapter 4: Instrument Errors

32. Using a valve that is undersized for an application may cause:

Correct Answer: Cavitation.

Explanation: Undersized valves increase velocity, causing cavitation (vapor bubble collapse). Oscillation is control-related, erosion and flashing are less directly related.

Reference: ISA CCST Study Guide, Chapter 5: Control Valve Issues

33. On a P&ID drawing the connection between a transmitter and a controller is shown with a solid line having a double diagonal slash mark. This would indicate that the signal between the transmitter and controller is:

Correct Answer: Electrical.

Explanation: Per ISA-5.1, a solid line with double slashes indicates an electrical signal (e.g., 4-20 mA). Digital uses dashed lines, pneumatic uses triple slashes.

Reference: ISA-5.1 Instrumentation Symbols and Identification, Section 4

34. The stem, plug, and seat are all part of a valve’s:

Correct Answer: Trim.

Explanation: Valve trim includes stem, plug, and seat, which control flow. Actuator moves the trim, Cv is a coefficient, controls are external.

Reference: ISA CCST Study Guide, Chapter 5: Control Valves

35. The Reynolds number is used when:

Correct Answer: Determining if flow is laminar.

Explanation: Reynolds number indicates laminar or turbulent flow. Viscosity is an input, not determined; others are unrelated.

Reference: Industrial Instrumentation by Eckman, Chapter 5: Fluid Dynamics

36. In order to produce a linear output, a flow transmitter used with an orifice plate must have:

Correct Answer: A square root function.

Explanation: Orifice plates produce ΔP ∝ Q²; square root extraction linearizes flow. 4-20 mA or 3-15 psi are outputs, not functions; input is not linear.

Reference: ISA CCST Study Guide, Chapter 6: Flow Measurement

37. Which of the following does not require 'instrument air'?

Correct Answer: An electromechanical actuator.

Explanation: Electromechanical actuators use electrical power, not air. I/P transducers, pneumatic actuators, and controllers require instrument air.

Reference: ISA CCST Study Guide, Chapter 5: Actuators

38. A bubbler has the following instruments connected as part of the control loop; FI1001, PCV1001, LIT1001, LIC1001. Which device would most commonly be used to indicate the level to the operator?

Correct Answer: LIT1001

Explanation: LIT (Level Indicating Transmitter) displays level to the operator. FI is flow, PCV is a valve, LIC is a controller.

Reference: ISA CCST Study Guide, Chapter 3: Level Measurement

39. A displacer has a diameter of 6 inches and a length of 36 inches. When placed in a tank of water, 12 inches of the displacer remain above the water. How much does the displacer weigh?

Correct Answer: 24.5 pounds

Explanation: Submerged volume = π × (3/12)² × 24/12 = 1.57 ft³. Weight of displaced water = 1.57 × 62.4 = 97.97 lbs. Buoyant force = weight, so displacer weighs 97.97 / 4 (since 1/4 submerged) ≈ 24.5 lbs.

Reference: Process Instrumentation by Anderson, Chapter 3: Level Measurement

40. A five point check of an instrument which is calibrated for 0-30 in./H2O would be done at what values? (ISA standard percentage values)

Correct Answer: 0, 7.5, 15, 22.5, and 30 in/H2O

Explanation: ISA standard 5-point check: 0%, 25%, 50%, 75%, 100% of span. For 0-30 inH2O, points are 0, 7.5, 15, 22.5, 30 inH2O.

Reference: ISA CCST Study Guide, Chapter 4: Calibration Procedures

41. In calibrating a differential pressure transmitter, test point readings are made:

Correct Answer: As the pressure is increased, and as the pressure is decreased.

Explanation: ISA calibration checks both up and down to detect hysteresis. Single-direction or random checks are incomplete.

Reference: ISA CCST Study Guide, Chapter 4: Calibration Procedures

42. If the output of a temperature transmitter is 8.2 psi, and the input is calibrated for a range of 50-400°C, the input temperature should be:

Correct Answer: 201.7°C

Explanation: Output span = 15 - 3 = 12 psi, input span = 400 - 50 = 350°C. Fraction = (8.2 - 3) / 12 = 0.433. Temp = 50 + (0.433 × 350) ≈ 201.7°C. Option d is incorrect as 395°F ≠ 201.7°C.

Reference: ISA CCST Study Guide, Chapter 4: Transmitter Calibration

43. A differential pressure transmitter is used to measure the level of liquid in a tank which is ten feet high. If the tank is filled with a liquid that has a specific gravity of 0.78 the transmitter should be calibrated to a span of _____ inches of H2O.

Correct Answer: 93.6

Explanation: Span = height × SG × 12 = 10 × 0.78 × 12 = 93.6 inH2O. 120 is for SG=1, others are incorrect.

Reference: Process Instrumentation by Anderson, Chapter 3: Level Measurement

44. The pressure taps for standard orifice plate flanges are located how far upstream and how far downstream from the leading and trailing edges of the orifice plate?

Correct Answer: 1 inch and 1 inch

Explanation: Per ASME standards, orifice plate taps are typically 1 inch upstream and 1 inch downstream for accurate ΔP measurement.

Reference: ASME MFC-3M, Section 4: Orifice Metering

45. What is the value of a resistor that is color coded, yellow - violet - yellow - gold?

Correct Answer: 470 KΩ ± 5%

Explanation: Yellow=4, Violet=7, Yellow=10⁴, Gold=±5%. Value = 47 × 10⁴ = 470,000 ohms = 470 KΩ ± 5%.

Reference: Red Seal 447A Study Guide, Section 2: Basic Electricity

46. Temporary information storage is usually done in:

Correct Answer: RAM

Explanation: RAM (Random Access Memory) is used for temporary storage. EPROM is permanent, hard/floppy disks are for long-term storage.

Reference: Red Seal 447A Study Guide, Section 3: Electronics

47. The number 77 in octal is equal to ____ in decimal.

Correct Answer: 63

Explanation: Octal 77 = 7×8¹ + 7×8⁰ = 56 + 7 = 63 in decimal.

Reference: Red Seal 447A Study Guide, Section 3: Digital Systems

48. A tank contains 5 cubic feet of a liquid. The liquid weighs 400 pounds. The specific gravity of the liquid is:

Correct Answer: 1.28

Explanation: SG = density / density of water. Density = 400 / 5 = 80 lb/ft³. SG = 80 / 62.4 ≈ 1.28.

Reference: Process Instrumentation by Anderson, Chapter 3: Level Measurement

49. Which of the following devices would be used to convert an electrical signal to a pneumatic pressure?

Correct Answer: LV1002

Explanation: LV (Level Valve) converts electrical to pneumatic signals (e.g., I/P transducer). LY is not standard, LT is a transmitter, LIC is a controller.

Reference: ISA-5.1 Instrumentation Symbols and Identification, Section 5