SACA Cheat Sheet 2026

The 30 highest-yield SACA facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. In robotic systems, what is the purpose of end effectors? → To interact with objects and perform tasks
2. Which protocol suite is specifically designed for wireless communication in industrial CPS environments requiring low power and mesh networking? → WirelessHART / ISA100.11a
3. In a CPS, what is the function of an actuator? → To convert control signals into physical action
4. What does LOPA stand for in functional safety risk assessment? → Layers of Protection Analysis
5. Which of the following best describes the role of sensors in a cyber-physical system? → To provide data input by measuring physical phenomena
6. What is a key characteristic of a cyber-physical system (CPS)? → It integrates computation with physical processes.
7. In Ladder Diagram programming, what does an 'XIC' (Examine If Closed) instruction do when the referenced bit is FALSE (0)? → It blocks continuity (prevents power flow), acting like an open switch
8. What does SIL stand for in the context of industrial functional safety? → Safety Integrity Level
9. In cyber-physical system design, what does 'functional safety' (IEC 61508) address? → Ensuring the system performs correctly even under fault conditions to avoid hazards
10. Which security threat is most specific to cyber-physical systems compared to traditional IT systems? → Physical damage via manipulated control signals
11. What is the role of edge computing in modern cyber-physical systems? → To process data near the source to reduce latency and bandwidth usage
12. In mechatronics, what is the purpose of a planetary gearbox attached to a servo motor? → To increase torque and reduce speed while maintaining compact dimensions
13. What communication standard is commonly used in cyber-physical systems to provide deterministic, real-time data exchange between control nodes? → OPC UA with TSN
14. Which of the following is a primary advantage of using a synchronous (timing) belt drive system compared to a standard V-belt drive? → Positive, slip-proof engagement for precise positioning
15. What is a common application of cyber-physical systems? → Autonomous vehicles
16. Which concept describes the digital replica of a physical asset used for simulation and monitoring in cyber-physical systems? → Digital twin
17. Which type of robot configuration consists of a robot arm with a fixed base and a rotating arm? → Articulated
18. What is the function of a 'current loop' in a servo drive amplifier? → To regulate the motor phase current, directly controlling torque with fast response
19. What is the purpose of a relay output module in a PLC system? → To physically switch external devices on and off
20. In a 6-axis articulated robot, what is the primary function of the first three axes (Axes 1, 2, and 3)? → Positioning the robot's wrist in space
21. Which PLC communication protocol operates at the application layer and is specifically designed for reading/writing data in Rockwell/Allen-Bradley controllers? → EtherNet/IP with CIP
22. What is the role of a microcontroller in a mechatronic system? → To control and process data
23. Which IEC standard specifically addresses Safety Instrumented Systems (SIS) for the process industry sector? → IEC 61511
24. What is the purpose of the PLC's watchdog timer? → To reset or halt the CPU if the scan cycle takes longer than a programmed time limit
25. Which sensor technology uses the interference of light waves to measure displacement with nanometer-level resolution in precision mechatronic systems? → Laser interferometer
26. Per IEC 60204-1, Stop Category 0 on a machine is defined as: → An immediate removal of power to the machine actuators
27. Which layer in the IIoT reference architecture is responsible for aggregating data from multiple field devices and performing initial processing? → Edge/fog layer
28. What is the primary function of a Filter-Regulator-Lubricator (FRL) unit in a pneumatic system? → To condition compressed air by filtering, adjusting pressure, and adding lubrication.
29. In mechatronic system design, what does 'bandwidth' of a servo control loop indicate? → The frequency range over which the closed-loop system can accurately track input commands
30. In a cyber-physical system, what is the primary function of the physical layer? → To interact with the real world through sensors and actuators