Process automation – sample exam questions

  1. What is process automation, and why is it significant in modern industries?
  2. Explain the difference between manual, automatic, and computer-based control.
  3. Define a "system" and explain its key characteristics.
  4. What is the difference between open and closed systems? Provide examples.
  5. What are the three types of processes based on the transformed element? Provide an example for each.
  6. Differentiate between discrete, continuous, and batch processes.
  7. What are the three main steps of a control system? Briefly explain each.
  8. What is the purpose of the ANSI/ISA 95 Standard in control systems?
  9. How do layers in the control hierarchy differ in terms of data complexity and time requirements?
  10. How did control systems evolve from early systems with relays to modern PLCs?
  11. What were the main drivers for developing PLCs?
  12. Describe the basic architecture of a PLC, including its key components.
  13. What is the purpose of galvanic isolation in PLC input/output modules?
  14. Differentiate between compact PLCs, modular PLCs, and soft PLCs.
  15. What are the advantages and limitations of small modular PLCs compared to large modular PLCs?
  16. What are the primary differences between a PLC and an industrial PC in terms of hardware, software, and maintenance?
  17. What are the main steps in a PLC program execution cycle?
  18. How does cycle time depend on factors like processor speed and program complexity?
  19. Explain the difference between system memory, working memory, and data memory in a PLC.
  20. Why is non-volatile memory important in PLC systems?
  21. What are the key features of the Beckhoff CX7000 PLC?
  22. How is the Beckhoff CX7000 programmed and configured?
  23. Why was the IEC 61131-3 standard introduced, and what are its main benefits?
  24. Name the five programming languages defined in the IEC 61131-3 standard and briefly describe their uses.
  25. How do PLC programming standards ensure the transferability of programs across manufacturers?
  26. Explain the significance of timers and counters in PLC programming.
  27. What are the differences between a program (PRG), a function block (FB), and a function (FUN)?
  28. Why are function blocks considered the most common type of POU in PLC programming?
  29. What is the purpose of global, local, and static variables in POUs?
  30. How are input, output, and memory addresses defined in a PLC? Provide examples.
  31. What are the potential issues with overlapping memory addressing, and how can they be avoided?
  32. What is a ladder diagram, and why is it widely used in PLC programming?
  33. Explain the role of horizontal and vertical connections in ladder diagrams.
  34. Describe the limitations of ladder diagrams when used in complex automation systems.
  35. How are timers (e.g., TON, TOF) and counters implemented in ladder diagrams?
  36. What is edge detection in ladder logic, and how is it achieved (e.g., R_TRIG, F_TRIG)?
  37. Describe how a memory cell (RS or SR) can be implemented using ladder diagrams.
  38. Provide an example where a timer is used to prevent premature motor direction reversal.
  39. What is a Function Block Diagram (FBD)? Explain the rules for connecting inputs and outputs in FBDs. Why is data type consistency important? How are feedback connections handled in FBDs?
  40. What is a Sequential Function Chart (SFC), and what are its key components (e.g., states, transitions, tokens)? What are the common risks (e.g., deadlocks) in complex SFC diagrams, and how can they be mitigated?
  41. Describe the basic structure of an Instruction List (IL) program.Why is IL considered obsolete in the IEC 61131-3 standard, and what are its primary drawbacks?
  42. What is Structured Text (ST), and how is it suited for complex data processing?
  43. Explain the precedence of operators in ST and provide an example of an expression.
  44. What are the advantages of using Structured Text over graphical programming languages like Ladder Diagrams?
  45. What is the importance of dividing a PLC program into states, and how does it improve system reliability?
  46. How is material tracking implemented using data unit types (DUTs) in TwinCAT?
  47. Outline the seven main components of PLC program organization.
  48. Why is it beneficial to combine FBD and SFC in automation projects?
  49. What is the role of sensors in a sensing system, and what can they measure? Provide examples.
  50. Define accuracy, precision, and sensitivity in the context of sensors.
  51. Explain the difference between digital and analog sensors. How is signal processing performed for each?
  52. How do inductive sensors detect metallic objects, and what is their operating principle?
  53. Compare capacitive and ultrasonic sensors. What materials are they best suited for detecting?
  54. Describe the working principle of optical sensors and explain the three types of configurations.
  55. What is the difference between incremental and absolute optical encoders? Provide examples of their applications.
  56. How does a laser-based position measurement system use phase shift to calculate distance?
  57. How do strain gauges work, and why are they commonly used in structural applications?
  58. Compare resistance temperature detectors (RTDs), thermistors, and thermocouples in terms of operation and industrial use.
  59. Why is the 4–20 mA standard used in industrial sensor wiring, and how does it prevent errors due to voltage drops?
  60. Differentiate between NPN and PNP sensors in terms of wiring and operation.
  61. What is the purpose of actuators in a control system, and how do they interact with final control elements?
  62. Explain the differences between pneumatic and hydraulic actuators in terms of operation and applications.
  63. What are the main advantages of using servo motors over stepper motors in precise positioning systems?
  64. What factors determine the choice of a motor (e.g., DC, AC, servo) in an industrial application?
  65. Describe the working principle of frequency converters and their role in controlling asynchronous motors.
  66. What are the roles of industrial communication buses in process automation?
  67. Explain the differences between Process Buses, Field Buses, and Sensor/Actuator Buses in terms of characteristics and applications.
  68. Compare the Master-Slave and Peer-to-Peer communication modes. What are their respective advantages and challenges?
  69. How does cyclic operation differ from event-driven communication? Provide examples of when each is preferred.
  70. What are the benefits and drawbacks of combining cyclic and event-driven communication approaches in industrial systems?
  71. What is the OSI model, and why is it adapted for industrial communication protocols?
  72. How does the TCP/IP model differ from the OSI model in industrial applications? Discuss real-time communication challenges.
  73. Compare electrical transmission media (e.g., twisted pairs, coaxial cables) with optical fibers in terms of speed, interference resistance, and cost.
  74. What are the advantages and limitations of using radio communication in industrial environments?
  75. Describe the physical layer and topology of the AS-i bus. What makes it suitable for binary signal transmission?
  76. What are the key features of the CAN protocol, and why is it widely used in automotive and industrial automation?
  77. What are the differences between Profibus variants (FMS, DP, PA), and where is each typically used?
  78. Explain the role of Profinet in industrial Ethernet communication. How does it support real-time and isochronous real-time communication?
  79. Why is modularity important in industrial communication systems? How does it simplify troubleshooting and expansion?
  80. How does the concept of topology affect the design and implementation of an industrial communication network?
  81. What is the OPC standard, and why was OPC UA introduced as an improvement over OPC Classic?
  82. Describe the two communication models in OPC UA: Client-Server and Publish-Subscribe.
  83. How does OPC UA ensure platform independence and enhance security?
  84. What are the key functionalities of OPC-DA, OPC-AE, and OPC-HDA in OPC Classic?
  85. What are the benefits of event-driven reading in OPC UA, and how does it differ from cyclic updates?
  86. What is the purpose of an MES system, and how does it bridge the gap between ERP and SCADA/PLC systems?
  87. What are the core functionalities of MES systems?
  88. Explain the ISA-95 standard and its significance in integrating business and production systems.
  89. What are the key advantages of implementing an MES system in modern manufacturing?
  90. What defines a "smart factory," and how does it relate to the Fourth Industrial Revolution?
  91. Discuss the role of the following technologies in a smart factory:
    • IIoT (Industrial Internet of Things)
    • Digital twins
    • Artificial intelligence and predictive maintenance
  1. How does a digital twin differ from a SCADA system in terms of functionality and application?
  2. What challenges do smart factories aim to address in modern manufacturing (e.g., labor shortages, environmental concerns)?
  3. Describe the concept of a digital twin and its impact on product design and process optimization.
Zadnja sprememba: ponedeljek, 13. januar 2025, 11.54