Week 5 - PLC Pneumatic Interfacing (MCQ) PDF

2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering Encoders and Absolute Encoders in Energy System Engineering Answers 1. What is the main difference between digital and analog sensors? A. Analog sensors are more reliable than digital sensors. B. Digital sensors can only b...

2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering Encoders and Absolute Encoders in Energy System Engineering Answers 1. What is the main difference between digital and analog sensors? A. Analog sensors are more reliable than digital sensors. B. Digital sensors can only be used for non-contact sensing, while analog sensors require physical contact. C. Digital sensors have transistor outputs while analog sensors have a continuous range of voltage or current. D. Analog sensors are faster than digital sensors. Answer: Digital sensors have transistor outputs while analog sensors have a continuous range of voltage or current. (C) Digital sensors have transistor outputs that are either ON or OFF, whereas analog sensors provide a continuous range of voltage or current. 2. What are the media used for sensing in digital sensors? A. Light, sound, electric field B. Temperature, vibration, force C. Heat, pressure, humidity D. Magnetic field, radio waves, infrared Answer: Light, sound, electric field (A) The media used for sensing in digital sensors include light, sound, and electric field. 3. In optical sensors, what is the most common type of light used for sensing objects? A. Infrared light B. Ultraviolet light C. X-ray light D. Visible light Answer: Infrared light (A) Infrared light is the most common type of light used in optical sensors to sense objects. 4. What is the primary purpose of pulsing the emitter in optical sensors? A. To reduce the sensor's lifespan B. To increase the emitter's lifespan C. To reduce power consumption D. To increase the sensor's sensitivity https://quizgecko.com/quiz/473156/print/answers 1/8 2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering Answer: To increase the emitter's lifespan (B) Pulsing the emitter in optical sensors is usually done to increase the emitter's lifespan. 5. In what context would a dark sensing optical sensor be more suitable compared to a light sensing one? A. For applications where objects are non-reflective and dark B. For applications where objects are highly reflective and bright C. For detecting objects with high reflectivity D. For detecting transparent objects Answer: For detecting transparent objects (D) Dark sensing optical sensors are more suitable for detecting transparent objects compared to light sensing ones. 6. How do contact sensors differ from non-contact sensors in terms of operation? A. Non-contact sensors detect without touching the component. B. Non-contact sensors must physically touch the object being sensed. C. Contact sensors generally have transistor outputs. D. Contact sensors are slower than non-contact sensors. Answer: Non-contact sensors detect without touching the component. (A) Contact sensors must have physical contact with the object being sensed, while non-contact sensors can detect without touching the component. 7. 'Diffuse reflective' sensors are more useful for what type of surfaces? A. **Transparent** surfaces B. **Opaque** surfaces C. **Translucent** surfaces D. **Shiny** surfaces Answer: **Opaque** surfaces (B) 'Diffuse reflective' sensors are more useful for **opaque** surfaces. 8. 'Diffuse reflective' sensors work well with what kind of objects? A. **Opaque** objects B. **Translucent** objects C. **Transparent** objects D. **Glossy** objects Answer: **Opaque** objects (A) 'Diffuse reflective' sensors work well with **opaque** objects. 9. What is the main difference between Absolute and Incremental Encoders? A. Absolute Encoders measure distance by using sound waves, while Incremental Encoders use a beam of ultrasonic sound as a sonar system. https://quizgecko.com/quiz/473156/print/answers 2/8 2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering B. Absolute Encoders use a unique pattern to represent each position of the disk, while Incremental Encoders are easier to interface because of fewer outputs. C. Absolute Encoders are available in various resolutions, while Incremental Encoders need a separate emitter-receiver for each bit. D. Absolute Encoders can use Gray code, natural binary, and BCD patterns, while Incremental Encoders use a transparent disk with opaque lines. Answer: Absolute Encoders use a unique pattern to represent each position of the disk, while Incremental Encoders are easier to interface because of fewer outputs. (B) Absolute Encoders use a specific pattern for each position, while Incremental Encoders are easier to interface due to fewer outputs. 10. How do Inductive Proximity Sensors work? A. They produce a (weak) magnetic field with an oscillator and coil, inducing eddy currents in metallic objects entering the field. B. They use an oscillator and electrode to produce an electrostatic field. C. They detect any type of object using a transparent disk with opaque lines. D. They measure distance by using sound waves and detecting the time for the wave to return. Answer: They produce a (weak) magnetic field with an oscillator and coil, inducing eddy currents in metallic objects entering the field. (A) Inductive Proximity Sensors work by producing a magnetic field that induces eddy currents in metallic objects, leading to voltage reduction sensed by detectors. 11. Why are Capacitive Proximity Sensors used? A. To detect ferrous objects by inducing eddy currents in metallic objects. B. To measure distance by using sound waves and detecting the time for the wave to return. C. To produce an electrostatic field and detect objects acting as capacitors. D. To detect any type of object using a transparent disk with opaque lines. Answer: To produce an electrostatic field and detect objects acting as capacitors. (C) Capacitive Proximity Sensors are used to produce an electrostatic field and detect objects acting as capacitors. 12. What is the purpose of Ultrasonic Sensors? A. To measure distance by using capacitors and detecting changes in voltage. B. To sense transparent objects by inducing eddy currents. C. To use a beam of ultrasonic sound as a sonar system for distance measurement. D. To use gray code for position representation on a disk. Answer: To use a beam of ultrasonic sound as a sonar system for distance measurement. (C) Ultrasonic Sensors utilize ultrasonic sound beams as a sonar system to measure distance. 13. How do Electric Field Sensors work? A. By using a separate emitter-receiver for each bit of position information. B. By using LED/Phototransistor pairs to sense the presence of objects. C. By producing eddy currents in metallic objects using a weak magnetic field. https://quizgecko.com/quiz/473156/print/answers 3/8 2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering D. By creating an electrostatic field and detecting changes in voltage. Answer: By creating an electrostatic field and detecting changes in voltage. (D) Electric Field Sensors utilize an electrostatic field and detect changes in voltage for sensing objects. 14. Which statement about Range of Proximity Sensors is true? A. The range is influenced by mass but allows flush mounting, with shielding reducing its effectiveness. B. The range is related to the size of the coil and is not affected by mass or material of the target. C. The range is not influenced by temperature changes and is sensitive to shielding. D. The range can be flush-mounted with inductor coils but is not impacted by mass or material of the target. Answer: The range is influenced by mass but allows flush mounting, with shielding reducing its effectiveness. (A) The range of Proximity Sensors can be influenced by mass, although they allow flush mounting. Shielding can reduce the effect of the range. 15. What is a characteristic of Diffuse Reflective Sensors? A. They use a beam of ultrasonic sound as a sonar system for distance measurement. B. They measure distance by detecting changes in voltage due to changes in capacitance. C. They use LED/Phototransistor pairs and are capable of ABSOLUTE or INCREMENTAL measurements. D. They cannot sense black color and are used to sense transparent objects. Answer: They cannot sense black color and are used to sense transparent objects. (D) Diffuse Reflective Sensors cannot sense black color but can be used to sense transparent objects. 16. What type of disk does an Absolute Encoder typically use for position representation? A. Disk with Gray code patterns. B. Opaque disk with transparent lines. C. Transparent disk with opaque lines. D. Disk with natural binary patterns. Answer: Transparent disk with opaque lines. (C) Absolute Encoders typically use a transparent disk with opaque lines for position representation. 17. How many wires are typically used in load powered sensors? A. Four wires B. Five wires C. Three wires D. Two wires Answer: Two wires (D) https://quizgecko.com/quiz/473156/print/answers 4/8 2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering In load powered sensors, typically two wires are used where one wire of the sensor is connected to power and the second wire is connected to the load (PLC input). 18. Which type of sensor has two power leads and an output lead in line powered sensors? A. Diffuse reflective sensors B. Light sensing sensors C. Optical sensors D. Dark sensing sensors Answer: Optical sensors (C) In line powered sensors, the three wire variety has two power leads and an output lead, which can be sourcing or sinking type. 19. In line powered sensors, what does a sourcing type sensor do? A. Current flows from load to sensor B. Current flows from sensor to load C. Current flows from sensor to power D. Current flows from power to sensor Answer: Current flows from sensor to load (B) A sourcing type sensor (PNP sensor) in line powered sensors allows current to flow from the sensor to the load. 20. Which type of sensor is more suitable for sensing transparent objects? A. Diffuse reflective sensors B. Optical sensors C. Light sensing sensors D. Dark sensing sensors Answer: Light sensing sensors (C) Light sensing sensors are more suitable for sensing transparent objects due to their ability to detect light variations. 21. What completes the circuit in load powered sensors? A. PLC input B. Load connection C. Sensor power leads D. Ground connection Answer: Ground connection (D) In load powered sensors, the circuit is completed by connecting the load to ground after connecting one wire of the sensor to power and the second wire to the load. 22. Which is a characteristic of three wire line powered sensors? A. Two output leads and one power lead B. Single power lead and single output lead https://quizgecko.com/quiz/473156/print/answers 5/8 2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering C. Single power lead and two output leads D. Two power leads and one output lead Answer: Two power leads and one output lead (D) Three wire line powered sensors typically have two power leads and one output lead, which can be either sourcing or sinking type. 23. What is the main difference between sourcing and sinking type sensors in line powered systems? A. The color of the wires B. The voltage requirements C. The number of wires used D. The direction of current flow Answer: The direction of current flow (D) 'Sourcing' and 'sinking' types in line powered systems differ mainly in the direction of current flow: from the sensor to the load for sourcing type and from the load to the sensor for sinking type. 24. Why are light sensing sensors preferred over dark sensing sensors for some applications? A. They can sense transparent objects better B. They consume less power C. They are more accurate D. They are less expensive Answer: They can sense transparent objects better (A) 25. What type of optical sensor can differentiate between colors? A. Focal Length Sensor B. Diffuse Reflective Sensor C. Special Reflective Sensor D. Color-differentiating Sensor Answer: Color-differentiating Sensor (D) The text mentions an Optical Sensor that can differentiate between colors based on the object's background color. 26. Which type of sensor can sense shiny objects using small prisms to polarize light? A. Focal Length Sensor B. Special Reflective Sensor C. Diffuse Reflective Sensor D. Color-differentiating Sensor Answer: Special Reflective Sensor (B) A special photo sensor is mentioned in the text that uses small prisms to polarize light for sensing shiny objects. 27. In which type of optical sensor is the receiver on when it cannot detect the beam from the emitter? https://quizgecko.com/quiz/473156/print/answers 6/8 2/29/24, 10:37 AM Encoders and Absolute Encoders in Energy System Engineering A. Special Reflective Sensor B. Focal Length Sensor C. Color-differentiating Sensor D. Diffuse Reflective Sensor Answer: Diffuse Reflective Sensor (D) The text describes the Dark-on mode where the sensor is on when the receiver cannot detect the beam from the emitter. 28. What kind of optical sensor emits light across a space and senses the light when not blocked by an object? A. Color-differentiating Sensor B. Diffuse Reflective Sensor C. Special Reflective Sensor D. Focal Length Sensor Answer: Diffuse Reflective Sensor (B) One type of optical sensor emits light across a space and senses it when the light is not blocked by an object. 29. Which optical sensor emits light to a specific focal point and senses the reflected light from that point? A. Color-differentiating Sensor B. Focal Length Sensor C. Diffuse Reflective Sensor D. Special Reflective Sensor Answer: Focal Length Sensor (B) The Focal Length Sensor, as mentioned in the text, emits light to a specific focal point and senses it when reflected back. 30. What is a characteristic of optical sensors that use fiber-optic cables? A. Large size and rigid B. Difficult to differentiate colors C. Small size and flexible D. Senses transparent objects easily Answer: Small size and flexible (C) Optical sensors with fiber-optic cables are described as having a small size and being flexible in the text. 31. Which optical sensor type cannot sense transparent objects? A. Diffuse Reflective Sensor B. Color-differentiating Sensor C. Focal Length Sensor D. Special Reflective Sensor Answer: Diffuse Reflective Sensor (A) It's mentioned in the text that Diffuse Reflective Sensors are not able to sense transparent objects. https://quizgecko.com/quiz/473156/print/answers 7/8 2/29/24, 10:37 AM https://quizgecko.com/quiz/473156/print/answers Encoders and Absolute Encoders in Energy System Engineering 8/8