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Communications Electronics for Ag. Machines ISOBUS

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Presentation on theme: "Communications Electronics for Ag. Machines ISOBUS"— Presentation transcript:

1 Communications Electronics for Ag. Machines ISOBUS
Lecture 8 ISO Part 6 / Virtual Terminal BAE 5030 – 503 Summer 2011 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University May 26, 2011 BAE

2 Virtual Terminal (VT) Concept
Serves as a “human interface” between operators and “implements” on an ISO bus VT provides both output (display) and input (buttons and controls) functionality to the operator A Working Set, a CF or Group of CFs, composes the logical entity that represents the implement that the operator interacts with VT provides a standardized means for displaying information and receiving operator input from a Working Set VT appears as exclusively available to a particular implement but multiple implements may use terminal simultaneously An Implement using the terminal is not necessarily aware of other Implements using the VT. Operator may switch the active panel and key inputs from one Implement to another. May 26, 2011 BAE

3 Virtual Terminal (VT) Example
Planter and Sprayer Simultaneously use Terminal Operator can switch to see either planter or sprayer planter or sprayer each have complete use of the terminal and may be unaware of each other Many other implements may also be connected, eg. tractor, GPS guidance system, task controller May 26, 2011 BAE

4 Example Virtual Terminals
A method on the terminal may be used to switch implements Implement 1 Implement 2 Implement 3 Implement 1 Data Mask Kvernland Tellus VT Soft Key Mask Implement 2 Implement 3 May 26, 2011 BAE

5 Working Set Definition
Working Set consists of a group of CFs created by one manufacturer and designed to work together as a single entity After Power-ON and successful Address claims each Working Set Master sends a stream of messages to the VT identifying: Master and number of members Each member of the working set The VT allows a Working Set Master and its members as a set to connect and use the terminal May 26, 2011 BAE

6 Network Model for VT Communications
Working sets consist of at least one master and may have slave CAs The VT communicates with the WS master. WS Master and slaves download Object Pool elements and interact with the VT. VT replies are sent to the WS Master (except configuration 4 and later are sent to the originator) Implement 2 Navigation / GPS May 26, 2011 BAE

7 Connection management
The VT when it is functional on the bus sends the VT Status message on change of status and once per second. Working Sets use this message to determine that the VT is operational and not busy. Loss of this message for longer than 3 seconds indicates to the WS that the VT has been turned OFF or is disabled. The Working Set Maintenance message is sent by the WS to the VT once per second when the working set has initialized VTs use this message to determine when the WS is operational Loss of this message for longer than 3 seconds indicates to the VT that the WS has been turned OFF, removed or disabled. If this is an unexpected shutdown, the WS’s object pool is deleted. May 26, 2011 BAE

8 Typical VT initialization message traffic
May 26, 2011 BAE

9 VT operator interface components
Data Mask Display Navigation Method 200 x 200 Min + + - - Mono 16 or 256 Color Edit Method ESC Soft Key Mask Display Auxiliary Assignment Method Soft Keys Control Method May 26, 2011 BAE

10 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 VT provides for methods of scrolling keys if virtual softkeys are provided VT informs WS of available keys in Metrics response Working Set controls menu hierarchy Soft Key Mask Display Text Go Stop Operator key selection method (Hard Keys) A B C D E F May 26, 2011 BAE

11 VT operator interface component examples
Case IH AFS Pro700 Navigation Touch Screen Soft Keys Touch Screen Control Method Parker ISOBUS VT Navigation DICKEYjohn X30 May 26, 2011 BAE

12 VT Interface Components
Auxiliary Input (Optional) May be built into VT or remote Working sets may contain Auxiliary Inputs and/or Auxiliary Functions Messages included to allow VT to: assign Auxiliary Inputs to Auxiliary Functions Auxiliary Input Types include Boolean ON/OFF and ON/OFF/ON Latched Non-Latching Etc. Analog Return to 0%, 50%, Quadrature Bi-directional encoder Touch screen / Mouse Support Button Object Auxiliary Input 1 Auxiliary Input 2 May 26, 2011 BAE

13 Auxiliary functions Auxiliary functions allow operator to control specific functions independent of the VT screen interface Auxiliary inputs (keys, switches, dials, knobs, sliders), provided by one or more working sets (or the VT), are active at all times after being assigned to an auxiliary function Auxiliary inputs are assigned to auxiliary functions (i.e. raise/lower, start/stop, set position) and are also provided by one or more working sets (or the VT). The operator assigns the inputs to the functions using a proprietary auxiliary assignment screen provided by the VT May 26, 2011 BAE

14 Auxiliary Function Example
Implement (working set) provides a “raise/lower implement” auxiliary function An auxiliary input, a two position momentary toggle switch, located on the armrest of the tractor (associated with the tractor ECU working set) of a type that is compatible with the auxiliary function is available The operator, using a screen provided by the VT, assigns this switch to the “raise/lower implement” function. The function of the switch does not change unless changed by the operator May 26, 2011 BAE

15 Auxiliary Function Assignment
Working Set masks contain Auxiliary Input objects Working Set masks contain Auxiliary Function objects A protocol is provided to allow WS to announce status of both auxiliary inputs and auxiliary functions VT provides a proprietary screen with auxiliary object designators (provided in the WS object pools) to allow operators to assign auxiliary inputs to functions 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 WTK Elektronik Multi-Functional-Handle May 26, 2011 BAE

16 VT Alarm Interface Components
Alarm Mask Object Defines screen Priority Assignable by Working Set When mask is selected by CF VT overlays entire Data Mask Area Active alarm masks are ordered highest priority first, then first alarm first Soft Keys can be used when the alarm is active Some acknowledgement method used to clear the alarm Acoustic Alarm Signal Object may be included Selectable duration, frequency, repetition, volume May 26, 2011 BAE

17 VT Language management
Language Message VT (virtual terminal) sends this message after the system has completed its power-on and address claims A default language is stored in the Tractor ECU and retrieved by the VT in case the desired language is not supported by the implement ECUs. The VT shall provide a method for the operator to view the supported language list of a connected implement or implement pool and to select a language from this list. Contains language code, number format, decimal symbol, date format, units for common parameter types, and units system May 26, 2011 BAE

18 Destination specific group function message
VT protocol Messages Destination specific group function message VT identifies sender via Source Address ECU identifies VT via Source Address May 26, 2011 BAE

19 Communication of Object Pools to a VT
Pool is Encapsulated in Transport Protocol One or more sessions may be used but only one type of TP Message sent to begin the pool is the: Object pool transfer message with a data field that contains VT Objects The message sent to finalize transmission of the pool is the: End of Object Pool message The VT responds with the: End of Object Pool response message Pool is a Collection of Objects in the data field of the Object Pool Transfer message Object Object ID Type Attributes and Data … Object Object ID Type Attributes and Data … Object Object ID Type Attributes and Data … And so on May 26, 2011 BAE

20 VT Object Transport Protocol
Used for pool transfer and for any 9 byte or longer messages Uses both standard Transport Protocol and Extended Transport Protocol Multi-packet message protocols Standard: Up to 1785 bytes message data Extended: 1786 to 117,440,512 bytes message data Connection management Sender: Requests to Send Receiver: Clear to Send n-Packets Sender: Sends cleared packets Receiver: Acknowledges completion Missed packets may be requested by receiver May 26, 2011 BAE

21 Extended Transport Protocol
Uses existing Connection Mode Transport Protocol with additional extended functions (BAM may not be used) Can transport up to 117,440,512 bytes (117 M bytes) Uses a sequence number offset to increase the range of packet sequence numbers Actual extended message sequence number = (ETP.DT Sequence number + ETP.CM_DPO Data Packet Offset) The ETP.CM_DPO Data Packet Offset is sent after every Clear to Send (ETP.CM_CTS) message to provide the extended sequence number Four new control functions are defined to distinguish the Extended Transport Protocol from the normal Transport Protocol Control Byte 20 Extended message Request To Send (ETP.CM_RTS) Control Byte 21 Extended message Clear To Send (ETP.CM_CTS) Control Byte 22 Extended message Data Packet Offset (ETP.CM_DPO) Control Byte 23 Extended message End of Message Acknowledgment (ETP.CM_EOMA) Standard connection abort message is retained May 26, 2011 BAE

22 Message sequence for the Extended Transport Protocol
May 26, 2011 BAE

23 Screen Description A mask defines screen and contains objects that describe screen elements A mask can define data screens, softkeys or alarms May 26, 2011 BAE

24 Example screen objects
Output String Line Boolean input Numeric Input List Input Picture Graphic Numeric Output Input Button May 26, 2011 BAE

25 Input and Output Fields
VT Display Objects Input and Output Fields String Numeric List input Shapes line rectangle ellipse polygon Picture Graphic (Bitmap) Seeding Rate 20,000 Choice #1 Choice #2 Choice #3 May 26, 2011 BAE

26 Complex Graphic Objects
Meter Object Bar Graph Object Arched Bar Graph May 26, 2011 BAE

27 WS updating a numeric display on a VT
Numeric value on the display can be updated with two CAN packets The VT responds and indicates if any error occurred May 26, 2011 BAE

28 Changes in object attributes
May be through commands from the WS or through event triggered macros May 26, 2011 BAE

29 Events signaled from the VT to the WS
VT Events including soft key press, button press, input object select, pointing events, escape, change numeric value, change Mask, change soft key mask, change string, hide/show user layout, and audio signal termination signal the WS through a message. May 26, 2011 BAE

30 Storage Management in a VT
Commands 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) May 26, 2011 BAE

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