Transcript Virtual Terminal

In-Vehicle Networking
for Heavy Duty Systems
Review of CAN / SAE J1939/ ISO 11783
Virtual Terminal
ISO 11783 Part 6
J1939-72
Virtual Terminal (VT) Concept
• Drill and Sprayer Simultaneously use Terminal
– Operator can switch to see either drill or sprayer
August 1, 2001
Virtual Terminal (VT) Concept
• Implements use terminal simultaneously.
– ECU or Group of ECUs compose a physical entity
(Implement) that the operator interacts with.
• Any Implement using the terminal is not aware
of other Implements using the VT.
• Operator may switch the active panel from one
Implement to another.
August 1, 2001
Example Virtual Terminal?
CNH AFS Terminal
Implement 1
Implement 2
Panel 1
Soft Keys
Panel 2
August 1, 2001
Implement 3
History
• Developed initially as DIN 9684 Part 4
German Agricultural Applications (ca. 1992)
• Determined necessary for ISO 11783 (Ag Bus)
– DIN 9684 imported to form ISO 11783 Part 6
– Other alternative from US proposed / rejected
– ISO 11783 Part 6 substantially revised based on:
• Field experiences with DIN 9684
• Technical objections
• Special ISO Task Force assigned to VT in 1999
– Re-Written Object Oriented Draft - Feb 2000
August 1, 2001
Evolution of ISO 11783 VT
• Based on DIN 9684 VT
– Authors of DIN 9684 were primary
participants in authoring
the ISO 11783 VT
• Major Improvements
Agrocom VT
–
–
–
–
Non-Volatile Storage Management
Simpler Object Oriented Design
More robust communications
Double bus speed
August 1, 2001
VT within the Vehicle Architecture
s
Bu
k
r
o
I
t
en
m
le
mp
etw
n
b
Su
Task Controller
Mgt. Computer
Gateway
VT
Management
Computer
GPS
Implement Bus
Implement ECU and
Implement Bridge
Tractor
ECU
Implement
ECU
Hitch
Transmission
Engine
Tractor Bus
Implement
ECU
ECU - Electronic Control Unit
August 1, 2001
Network Model for VT Communications
Implement 1
Working Set
1
ECU
NAME=X
ECU
NAME=W
ECU
NAME=Y
ECU
NAME=V
Working Set
2
ECU
NAME=Z
ECU
NAME=T
Implement 2
Navigation / GPS
August 1, 2001
ECU
NAME=B
Virtual
Terminal
Working Set Definition
• Working Set consists of a group of ECUs
created by one manufacturer and designed to
work together as an entity.
• After Power-ON and successful Address claims
the Master sends a stream of messages to the
VT identifying:
• Master and number of members
• Each member of the working set
August 1, 2001
VT operator interface components

Data Mask Display
200 x 200
Mono Min
or 16 Color


++
-
ESC
Soft Key Mask Display
Edit
Method
Auxiliary
Assignment
Method
Soft
Keys
Control
Method
August 1, 2001
Navigation
Method
VT Interface Components
• Required Elements
– Soft Keys
– Method for editing
character and numeric
input, enter/escape
– Method for navigating
between fields
– Method to select
Implement
(Working Set)
August 1, 2001
VT Interface Components
• Auxiliary Input (Optional)
• May be built into VT or remote
• Messages included for VT to:
configure remote auxiliary
input device across network
– Auxiliary Input Types include
• ON/OFF (Boolean)
• Analog
Deere and Co.
50 Series Combine
BUTTON
August 1, 2001
Mou
– Button Object
se
• Touch screen / Mouse Support
Auxiliary Function Assignment
• Working Set sends Auxiliary Function Objects
• VT uses any stored previous assignments
• VT notifies Working Set of assignment of Input
Functions to Objects
• Working Set acknowledges
• Operator may re-assign Input Functions
August 1, 2001
Deere and Co.
50 Series Combine
VT Alarm Interface Components
• Alarm Mask Object
ALARM
– Defines screen
• Priority
– Assignable by Working Set
WHEEL FELL
OFF!
• When mask is selected
– VT overlays Data Panel
– Highest priority, then first alarm
– Soft Keys can be used
• Acoustic Alarm Signal
– Selectable duration, frequency, repetition, volume
August 1, 2001
Soft Keys
• Soft Key Mask created by Working Set is used
to define displayable information and Key Code
• One set of Keys (a Mask) may be selected at a
time by the Working Set
• Working Set or ECU controls hierarchy
Soft Key Mask Display
Text
Soft
Keys
A
B
C
Go
Sto
p
D
E
August 1, 2001
F
VT Commands and Responses
• Group Function Message
• VT identifies sender via Source Address
• ECU identifies VT via Source Address
Identifier
1 1 0 0 0
Data
Field
VT_to_ECU
or
ECU_to_VT
ECU
or
VT
VT
or
ECU
VT PGNs
Destination Address
1 Byte
1 Byte
VT Function No.
1 Byte
Source Address
1 Byte
VT Function Parameters
-----------
7 Data Bytes ------------------
---------------------- VT Function ------------------August 1, 2001
VT Object Transport Protocol
• Uses ISO 11783 Transport protocol
– Multi-packet message protocol
– Up to 1785 bytes message data
– Connection management
•
•
•
•
•
Sender:
Receiver:
Sender:
…
Receiver:
Requests to Send
Clear to Send n-Packets
Sends cleared packets
Acknowledges completion
– Missed packets may be requested by receiver
August 1, 2001
Communication of Object Pools to a VT
• Pool is Encapsulated in Transport Protocol
– One or more sessions may be used
• Pool is a Collection of Objects
Object 1 Object ID Type Attributes and Data …
Object 2 Object ID Type Attributes and Data …
Object 3 Object ID Type Attributes and Data …
…
And so on
August 1, 2001
Hierarchical Structure for Screen Description
Working Set
Mask
(Data, Alarm, Soft Key)
Macro
Macro
Container
SCREEN
Input Field
Graphical
PANEL
Outut Field
Outut Field
August 1, 2001
VT Display Objects
• Input and Output Fields
• String
• Numeric
• List input
• Shapes
•
•
•
•
Seeding Rate
20,000
Choice #1
Choice #2
Choice #3
line
rectangle
ellipse
polygon
• Picture Graphic (Bitmap)
August 1, 2001
Complex Graphic Objects
• Meter Object
• Bar Graph Object
• Arched Bar Graph
August 1, 2001
Updating a numeric display on a VT
Working Set
ECU
Output NumberField
Font Attribute
Value Attribute
Scale Attribute
Offset Attribute
Change Value Attribute
August 1, 2001
VT Events and Commands
Working Set
Object
EVENT
EVENT
Command
e
g
an
Macro
Command
Object
Attribute
Command Ch
ang
Attribute
e
Attribute
Ch
August 1, 2001
ECU
Storage Management in a VT
ma
nd
ECU
Volatile
On-line Storage
Co
m
VT Storage
Load
Working Set
Resource Pool
Non-Volatile
Off-line Storage
Resource Pool
Version 1
Save
Resource Pool
Version 2
August 1, 2001
Non-Volatile Storage Functions
• Get Versions
• List of all version labels for Working Set.
• Store Version (by Label)
• Stores volatile resources of Working Set.
• Load Version (by Label)
• Delete Version (by Label)
August 1, 2001
Initialization Message Traffic
Working Set
VT
Address Claim
t
Address Claim Reques
Address Claims
Working Set De
fi
Request VT Ch
nition
aracteristics
VT Characteristics
Object Pool
End of Pool
End of Pool Response
Working Set
Command and
VT Reply Traffic
August 1, 2001
VT Connection Management
• VT Status Message (From VT)
• Periodic @ 1s
• Transmits visibility of Masks, Current command
• Transmits VT Busy Status
• Working Set Maintenance Message (From WS)
• Periodic @ 1s
• Allows VT to determine of loss of WS
• 3 second missing indicates loss of connection
• VT releases memory
• Working Set takes “Safe Mode”
August 1, 2001
VT Like Products
August 1, 2001
Operator Interface Elements of a VT
Storage
Network
Interface
Mouse
Soft
Keys
Screen
Hard
Keys
Auxillary
Inputs
August 1, 2001
VT Messages
• VT - PGNs
• Network Management
• Address requests
• Address Claims
• Working Set Management
• Transport Protocol
• Language Message
August 1, 2001