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Communications Electronics for Ag. Machines ISOBUS

Communications Electronics for Ag. Machines ISOBUS. Lecture 8 ISO 11783 Part 6 / Virtual Terminal BAE 5030 – 503 Summer 2011 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University. Virtual Terminal (VT) Concept.

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Communications Electronics for Ag. Machines ISOBUS

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  1. Communications Electronics for Ag. Machines ISOBUS Lecture 8 ISO 11783 Part 6 / Virtual Terminal BAE 5030 – 503 Summer 2011 Instructor: Marvin Stone Biosystems and Agricultural Engineering Oklahoma State University BAE 5030-503

  2. Virtual Terminal (VT) Concept • Serves as a “human interface” between operators and “implements” on an ISO 11783 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. BAE 5030-503

  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 BAE 5030-503

  4. Example Virtual Terminals • A method on the terminal may be used to switch implements Implement 1 Implement2 Implement3 Implement 1 Data Mask KvernlandTellusVT Soft Key Mask Implement2 Implement3 BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  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. BAE 5030-503

  8. Typical VT initialization message traffic BAE 5030-503

  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 BAE 5030-503

  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 A B C D E F Operator key selection method (Hard Keys) BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  18. VT protocol Messages • Destination specific group function message • VT identifies sender via Source Address • ECU identifies VT via Source Address BAE 5030-503

  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 1Object ID Type Attributes and Data … Object 2Object ID Type Attributes and Data … Object 3Object ID Type Attributes and Data … … And so on BAE 5030-503

  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 BAE 5030-503

  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 BAE 5030-503

  22. Message sequence for the Extended Transport Protocol BAE 5030-503

  23. Screen Description • A mask defines screen and contains objects that describe screen elements • A mask can define data screens, softkeys or alarms BAE 5030-503

  24. Example screen objects Output String Line Boolean input Numeric Input List Input Picture Graphic Numeric Output Input Button BAE 5030-503

  25. 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 BAE 5030-503

  26. Complex Graphic Objects • Meter Object • Bar Graph Object • Arched Bar Graph BAE 5030-503

  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 BAE 5030-503

  28. Changes in object attributes • May be through commands from the WS or through event triggered macros BAE 5030-503

  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. BAE 5030-503

  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) BAE 5030-503

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