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选择+简答代写-EMESTER 2
时间：2021-03-08
[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.
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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
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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.
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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
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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.
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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
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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
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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
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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
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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
学霸联盟
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
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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.
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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
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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.
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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
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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
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