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[EEE8105] NEWCASTLE UNIVERSITY School of Engineering _____________________ SEMESTER 2 2018/2019 _____________________ DISTRIBUTED CONTROL SYSTEMS Time allowed – TWO hours All questions in Section A must be answered in the accompanying answer sheet. ONLY ONE question from Section B must be answered. [Turn over EEE8105 Page 2 of 11 Section A [70 Marks] You must answer ALL questions in this section. Select the best answer and mark on the accompanying answer sheet. [All questions in this section carry equal marks] Do not forget to write your student number on the accompanying answer sheet. 1. In the three-level hierarchical model describing automated manufacturing systems, CAN bus can be used for: A. Communication within the Discrete Process Layer. B. Communication between the Discrete Process Layer and the Information layer. C. Communication within the Information Layer. D. A and B are correct. E. A, B and C are correct. 2. When transmitting a digital signal with a bit rate of 100 Mbit/sec across a wired copper network, the signal will mostly be affected by: A. Propagation delay. B. Signal reflection. C. Skin effect. D. Line noise. E. Crosstalk. 3. Bus repeaters are used to: A. Allow Bus extension. B. Compensate for attenuation. C. Connect the two parts of the common bus if the cable breaks. D. A and B are correct. E. A, B and C are correct. 4. Which of the following may be used to establish the message’s priority and identity within the CAN data frame A. The 11-bit identifier. B. The 29-bit identifier. C. The Token Hold Time. D. A and B are correct. E. A, B and C are correct. EEE8105 Page 3 of 11 5. Bit-stuffing may be required when using: A. Manchester Encoding data representation. B. RZ (return-to-zero) data representation. C. Long data frames. D. B and C are correct. E. A, B and C are incorrect. 6. Which of the following is true about the physical connection of a CAN transceiver to a Fieldbus A. It can be described as a Wired-OR connection. B. The Recessive bit is logic “1”. C. It can be described as a Wired-NAND connection. D. A and C are correct. E. B and C are correct. 7. Which of the following is true about the CANopen protocol A. Its Data Link Layer includes four ISO/OSI layer entities. B. It makes use of only the Application Layer and Physical Layer of the ISO/OSI reference model. C. It makes use of only three layers of the ISO/OSI reference model. D. A and C are correct. E. A, B, and C are incorrect. 8. Which of the following may be used for transmitting data at 5 Mbit/sec over a 100 m distance A. Copper wires. B. Co-axial cable. C. Optical Fibre. D. B and C are correct. E. A, B and C are correct. 9. The limitations of a Centralized Controller Cell include: A. Troubleshooting becomes difficult with a large number of components. B. Mechanical linkages and pneumatic components cannot be used. C. Parallel conveyor belts cannot be used. D. Only one set of communication wires plus power lines can be used. E. A and B are correct. 10. In the CAN bus system, propagation delay can be compensated for by: A. Providing programmable time segments by the Bit Timing Logic. B. Using a higher clock frequency for the Bit Stream Processor. C. Using repeaters. D. A and B are correct. E. A, B and C are correct. [Turn over EEE8105 Page 4 of 11 11. Which of the following is true about a CAN error frame A. Its Start of Frame field is composed of a single Dominant bit. B. Its End of Frame field is composed of 7 Recessive bits. C. It has no data field. D. A, B and C are correct. E. A, B and C are incorrect. 12. Which of the following could be an Error Flag produced by a CAN node A. Bus-Standby. B. Error Passive. C. Overload. D. A and B are correct. E. A, B and C are correct. 13. The Application Layer of the ISO/OSI Reference Model is responsible for: A. Syntax transformation including data transformation, formatting and special transformations such as data compression. B. Checking the authenticity and authority of the communications link end systems. C. Stripping off the Protocol Control Information added by the different layers at the transmitter end. D. A and B are correct. E. B and C are correct. 14. The Physical Layer of the ISO/OSI Reference Model is responsible for: A. Defining physical connections to the medium including plug types and pin connections. B. Translating the data into some form of transmittable signal, and translating incoming messages back into usable data. C. Generating control signals for proper operation of the Application Layer – e.g. collision and bad signal detection. D. A and B are correct. E. A, B and C are correct. 15. Which of the following is true about Full CAN implementation A. Individual sections or objects of the message buffer memory are reserved for the transmission or reception of CAN frames with pre-set programmable identifiers. B. The controller receives all messages irrespective of their identifier. C. A software routine must be invoked every time a CAN message is received. D. A and B are correct. E. A, B and C are correct. EEE8105 Page 5 of 11 16. Which of the following is true about an Embedded CAN controller A. Only CAN hardware is encapsulated in one physical integrated circuit. B. CAN protocol is implemented by software within a microcontroller. C. It is not suitable for Full CAN message filtering implementation. D. B and C are correct. E. A, B and C are incorrect. 17. The Error Management Logic in a CAN controller is used for: A. Storing error record in The Message Buffer Memory. B. Sends information about errors to the CPU Interface Logic. C. Differentiating between the frame types and detecting frame errors. D. A and C are correct. E. A, B and C are correct. 18. Which of the following is true about the ISO/OSI Reference Model A. It is a framework to support the development and implementation of open communication protocols. B. It is based on the assumption that there are two co-operating systems wishing to communicate. C. All the 7 layers of the model add, to each data unit, control information to organise the communication between the peer entities in the two remote systems. D. A and B are correct. E. A, B and C are correct. 19. The Transport Layer of the ISO/OSI Reference Model is responsible for: A. Segmenting large data structures (or files) into smaller transmittable sections. B. Providing high-level data communication functions between network users. C. Bridging the gap between the layers that provide data transmission functions and the layers that provide communication functions. D. A and C are correct. E. B and C are correct. 20. The Bit Stream Processor of a CAN controller is responsible for: A. Storing individual CAN objects for transmission or reception. B. Controlling the entire protocol, differentiating between the frame types and detecting frame errors. C. Synchronisation at the start of the frame and re-synchronisation on further transitions during reception of the frame. D. A and C are correct. E. B and C are correct. [Turn over EEE8105 Page 6 of 11 21. The Bit Timing Logic of a CAN controller is responsible for: A. Differentiating between the frame types and detects frame errors. B. Deriving a suitable clock frequency for the CAN controller based on the frequency of an external clock oscillator. C. Determining the timing of the bits and maintaining the CAN controller synchronised with the edges of the bit stream on the CAN bus. D. B and C are correct. E.
A, B and C are incorrect.
22. The Transceiver Control Logic of a CAN controller is responsible for: A. Determining the timing of the bits and maintaining the CAN controller synchronised with the edges of the bit stream on the CAN bus. B. The use of global status and control registers in the communication objects. C. Bit Stuffing. D. A and B are correct. E. A, B and C are incorrect. 23. The Presentation Layer of the ISO/OSI Reference Model is responsible for: A. Session establishment and termination requests. B. Syntax transformation including data transformation, formatting and special transformations such as data compression. C. Normal and Expedited data exchange. D. A and B are correct. E. B and C are correct. 24. Which of the following is true about a CAN data frame with an 11-bit identifier A. The Cyclic Redundancy Check field contains 16 bits. B. The Data field can hold between 0 and 8 bytes of data. C. The Start of Frame field is composed of a single Dominant bit. D. A and B are correct. E. A, B and C are correct. 25. The Data Link Layer of the ISO/OSI Reference Model is responsible for: A. Dealing with transmission errors and thus minimising the number of errors passed on to the higher layers. B. Segmenting large data structures (or files) into smaller transmittable data frames. C. Reconstructing large data structures from the smaller data frames received. D. A and B are correct. E. A, B and C are correct. EEE8105 Page 7 of 11 26. The Network Layer of the ISO/OSI Reference Model is responsible for: A. Setting up associations between users or application processes, and for the termination of information exchanges. B. The addressing and routing functions needed to transport messages between the end systems involved. C. Synchronisation on start-up and re-establishment of connections after link failures. D. A and B are correct. E. B and C are correct. 27. The Arbitration field of a CAN data frame may include: A. 12 bits. B. 22 bits. C. 32 bits. D. A and C are correct. E. A, B and C are incorrect. 28. The Start of Frame field of the standard CAN data frame is composed of: A. A single Dominant bit. B. Two Dominant bits. C. One Dominant bit followed by one Recessive bit. D. Seven Recessive bits. E. A, B, C and D are incorrect. 29. If the Remote Transmission Request bit in the CAN data frame is set Dominant, it indicates that: A. The frame is a Remote Frame. B. The Arbitration Field is 29 bits. C. The frame contains Data. D. A and B are correct. E. B and C are correct. 30. If a CAN node sends an error flag composed of six Dominant bits, this means that: A. The device believes that it is the cause of the error. B. The device is completely sure that an error has occurred and that this error was not its own fault. C. The device ceases to participate in the communication so as not to disturb other nodes on the bus. D. A and C are correct. E. A, B, and C are incorrect. [Turn over EEE8105 Page 8 of 11 31. Which of the following is correct about the Poll/Select MAC method A. Only one station on the network is allowed to initiate transmissions. B. The master node will only request information from a device once its previous request has been successfully completed. C. A priority system is used to avoid data collision. D. A and B are correct. E. B and C are correct. 32. Which of the following is correct about the Token Ring MAC method A. It is used with a Ring Network to overcome fault arisen from a cut in the field bus. B. Its performance depends on the choice of the Token Hold Time (THT) for the different nodes. C. The Token is comprised of 7 Recessive bits. D. A and B are correct. E. B and C are correct. 33. Which of the following is correct about the Slotted Ring MAC method A. The network is initialised with a fixed number of bits for transmission by the master node. B. When a node detects an empty slot it fills in the frame with data and the destination address for the data. It then marks the slot as full. C. The time taken to transmit data increases with the number of nodes in the ring. D. A and B are correct. E. B and C are correct. 34. Which of the following can be considered as Strategic Criteria in Network Selection A. Software and services cost. B. Data bus length and expandability. C. Speed, reaction time and propagation delay. D. A and C are correct. E. A, B, and C are incorrect. 35. If a CAN controller supports 29-bit identifiers passively. This means: A. It uses only the standard 11-bit identifier. B. It uses only the 29-bit identifier. C. It can use both the 11-bit and 29-bit identifier types. D. It has an 8-bit microprocessor. E. A, B, C, and D are incorrect. END OF SECTION A EEE8105 Page 9 of 11 Section B [30 Marks] You must answer ONLY ONE question from this section. [All questions in this section carry equal marks] In your answer to this section, clearly show all working. Question 1 [30 Marks] NODE B ID:11001011000 AM: 00000000 AC: 00000111 NODE A ID:01101101101 AM: 00001100 AC: 11000111 NODE C ID:01011100011 AM: 01000010 AC: 11000011 AM = Acceptance Mask AC = Acceptance Code ID = 11-bit Identifier Figure 1 a) Figure 1 shows three nodes (A, B, and C) of a CAN network. The network is implemented using CAN Specification 2.0 and uses an 11-bit identifier system. Each node uses the Basic CAN software implementation to filter the received messages. i. Given the Basic CAN settings in figure 1, will Node B accept a message transmitted by Node A [4 Marks] ii. Node B reports a fault on the CAN network. Closer inspection of the system shows that Node B has set a Bus-Off Error Flag. Where in the CAN network would you look to resolve this problem Explain your answer. [4 Marks] iii. At a given time Node A and Node C simultaneously attempt to transmit data onto the Fieldbus. Which node will win the arbitration process [4 Marks] iv. A fourth node, D, is to be integrated into the CAN network. Unlike existing nodes in the network, Node D will be used to capture and store all message data transmitted across the bus. Describe how you would integrate this node into the network. [4 Marks] Question 1 continues on the next page EEE8105 Page 10 of 11 SOF Control Field Data Field Error Checking EOF 0 1 1 0 0 1 0 0 1 1 1 1 1 1 1 1 0 1 1 Figure 2 b) Consider the data frame shown in figure 2. i. By implementing bit stuffing and applying a non-return to zero transmission system, draw a diagram to show how this data frame would look as serial data on a communication bus. [4 Marks] ii. Calculate the protocol efficiency. [2 Marks] iii. The frame represents data which has arrived at a receiver node. The error checking bits are generated by a Cyclic Redundancy Check (CRC) of the data field at the transmitter. The CRC mechanism uses a generator polynomial, G(x) = 11011. Determine whether the message data has arrived at the receiver correctly, or not. [8 Marks] Question 2 [30 Marks] NODE B ID = 11001100011 AM: 01000101 AC: 10100101 AM = Acceptance Mask AC = Acceptance Code ID = 11-bit Identifier NODE A ID = 10100000011 AM: 10101010 AC: 01010101 NODE C ID = 00000000000 AM: 11111111 AC: 00000000 NODE D ID = 11001011111 AM: 00111000 AC: 10000111 NODE E ID = 11111111111 AM: 00000000 AC: 11111111 Figure 3 a) Figure 3 shows five nodes (A, B, C, D and E) of a CAN network. The network is implemented using CAN Specification 2.0 and uses an 11-bit identifier system. Each node uses the Basic CAN software implementation to filter the received messages. Question 2 continues on the next page EEE8105 Page 11 of 11 i. At a given time, nodes B, D and E attempt to transmit data onto the Fieldbus. Draw a timing diagram to demonstrate the bus arbitration mechanism that will take place in the network. Clearly, show the signal transmitted onto the Fieldbus and the response of each transmitting node up until the point when a single node wins the arbitration process. [7 Marks] ii. At a given time, Node A transmits a CAN frame onto the Fieldbus. Determine which nodes in the network will accept this message. [8 Marks] iii. If the Full CAN hardware implementation is used, instead of the Basic CAN software implementation, explain how the different nodes in the network will perform message filtering. [8 Marks] B7 B6 B5 B4 B3 B2 B1 B0 Row Parity Check Data (1) 0 0 0 0 0 0 1 0 1 Data (2) 0 1 0 1 0 0 0 0 0 Data (3) 1 0 0 0 0 1 1 0 1 Data (4) 0 1 0 0 0 0 0 0 1 Data (5) 0 1 0 1 1 1 0 1 0 Data (6) 1 0 0 0 0 0 0 0 1 Data (7) 1 1 0 0 0 0 1 1 0 Data (8) 0 0 0 0 0 1 1 1 1 Column Parity Check 1 0 0 0 1 0 0 1 Figure 4 b) Figure 4 shows a set of data frames received by a receiver that uses block parity (logic sense: EVEN) for error detection. i. Determine whether the data has arrived correctly, or not. [2 Marks] ii. If you believe there is an error, specify which bit(s) have been received incorrectly, and briefly discuss the options for error correction. [3 Marks] iii. Give one example of data error that cannot be detected by this error checking mechanism. [2 Marks] END