190302dB

Question 1

What is multiplexing?

Answer 1

ability to send and receive digital electronic signals over a pair of wires at high speed

Question 2

benefits of using a data link?

Answer 2

minimizes amount of electrical wiring, reduces size and cost of wiring harnesses + components. can add components easily

Question 3

what 3 multiplex networks and protocols does off-road equipment use?

Answer 3

J1587/J1708, J1939/CAN, ISO11783/CAN

Question 4

Is there a master control device in a CAN network?

Answer 4

No

Question 5

What is the device that’s designed to follow the CAN protocol?

Answer 5

a transceiver chip

Question 6

How is priority determined in a message?

Answer 6

priority code is embedded in

Question 7

Purpose of data links?

Answer 7

connect systems and communicate info form one module to another

Question 8

What does ISO stand for?

Answer 8

international organization for standardization

Question 9

What does ISO do?

Answer 9

implements international proprietary, industrial and commercial standards

Question 10

What does SAE do?

Answer 10

set industry standards for electronic control systems and diagnostics

Question 11

What is a baud rate?

Answer 11

speed of data transfer over the network. In kb/s or Mb/s

Question 12

What is a backbone?

Answer 12

network method of connection. most common is twisted pair with shielded connection

Question 13

What is a stub?

Answer 13

segment of data link. max 1 meter in length (like a road off the main highway)

Question 14

What is a node?

Answer 14

a computer or device that has a unique network address ( a house)

Question 15

What is a terminating resistor?

Answer 15

placed at each end of the data link. reduces electrical interference ( a cul-de-sac at the end of the road)

Question 16

What are standing waves?

Answer 16

electrical reflections or waves, causes problems with module communication

Question 17

What is a Vehicle communication data bus?

Answer 17

communication network that connects to all the multiplexed components of the system

Question 18

What is a protocol?

Answer 18

common language for data communication between modules.

Question 19

What is Controller Area Network?

Answer 19

communication protocol for on-highway trucks

Question 20

What are data links?

Answer 20

Provide transmission of input and output signals between nodes and diagnostic scan tools

Question 21

What does a non-shielded twisted pair cable contain?

Answer 21

a twisted pair of wires protected by a plastic coating

Question 22

What does a shielded twisted pair cable contain?

Answer 22

non-insulated copper wire (drain). wires are wrapped in tin foil and uses plastic coating for insulation

Question 23

What is the drain wire used for?

Answer 23

prevents interference from entering data link

Question 24

Why are conductors twisted?

Answer 24

1. provide immunity to magnetic fields
2. enables conductors to maintain constant capacitance

Question 25

Twisted pairs have how many twists per foot?

Answer 25

12 per linear foot

Question 26

What is topology?

Answer 26

logic structure of control modules on data bus (a neighborhood)

Question 27

Characteristic of loop/ring topology?

Answer 27

all modules wired in series

Question 28

Disadvantage of loop topology?

Answer 28

if one module loses power/ground, all modules will lose communication

Question 29

characteristic of star topology?

Answer 29

contains a master module in the centre and slave modules

Question 30

Characteristic of linear topology?

Answer 30

has a backbone with stubs running to each module. there is no master module

Question 31

What are the disadvantages of SAE J1587/J1708?

Answer 31

1. if one part of network fails, it will become non-functional 2. slow communication speed

Question 32

What is a message identifier?

Answer 32

indicates source address of transmitting node

Question 33

What is a parameter identifier?

Answer 33

indicates to what parameter the following data correspondsa

Question 34

What is a parameter data byte?

Answer 34

Parameter identifier (PID) is followed by one data value.

Question 35

What is a checksum?

Answer 35

final byte of data

Question 36

What are the standards for cabling and connectors on J1587/J1708?

Answer 36

max bus length: 40m Max # of nodes: 20 unshielded twisted pair orange and white does not need terminating resistors has gold plated pins

Question 37

What kind of topology does SAE J1939/CAN use?

Answer 37

linear topology

Question 38

What design is used for J1939 cabling?

Answer 38

twisted pair of wires Green and yellow can be shielded or unshielded

Question 39

If one terminating resistor is missing, what will be seen?

Answer 39

communication glitches

Question 40

if both terminating resistors are missing, what will be seen?

Answer 40

all communication will fail

Question 41

in a j1939 system, what does a total loss of communication indicate?

Answer 41

a voltage or hardware problem

Question 42

in a j1939 system, what does a partial loss of communication indicate?

Answer 42

data bus device failure

Question 43

what colour wires are used in ISO11783?

Answer 43

green, blue, red, black

Question 44

How do the ISO11783 wires correlate?

Answer 44

red and black are used as a backbone (terminating bias circuit) and green and blue are used like J1939

Question 45

what is the purpose of ISOBUS standardizing the data bus breakaway connector?

Answer 45

so that any make of machine is compatible with any make of implement

Question 46

What replaces the PID in a J1939 message?

Answer 46

suspect parameter number (SPN)

Question 47

When performing the CAN data wire ground fault test, what is the expected reading of a properly functioning system?

Answer 47

1Mohm-4Mohm

Question 48

When performing the terminating resistor test on a J1939 data link, what does a reading of less than 60ohm indicate?

Answer 48

short

Question 49

What is the construction of an ISO11783 cable?

Answer 49

unshielded twisted quad

Question 50

2 functions of a terminating bias circuit?

Answer 50

uses battery power + ground supply along with can high and can low to provide electrical bias and termination to the network, preventing reflections from occurring in the system that would create interference