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Communications Electronics for Ag. Machines ISOBUS Lecture 8 ISO 11783 Part 6 / Virtual Terminal BAE 5030 – 503 Summer 2011 Instructor: Marvin Stone Biosystems.

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Presentation on theme: "Communications Electronics for Ag. Machines ISOBUS Lecture 8 ISO 11783 Part 6 / Virtual Terminal BAE 5030 – 503 Summer 2011 Instructor: Marvin Stone Biosystems."— 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, 2011BAE

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, 2011BAE

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, 2011BAE

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

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, 2011BAE

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) May 26, 2011BAE Navigation / GPS Implement 2

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, 2011BAE

8 Typical VT initialization message traffic May 26, 2011BAE

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

10 Operator key selection method (Hard Keys) 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 May 26, 2011BAE Soft Key Mask Display ABCDEF TextGoSto p

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

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 May 26, 2011BAE Auxiliary Input 1 Auxiliary Input 2

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, 2011BAE

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, 2011BAE

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 May 26, 2011BAE WTK Elektronik Multi-Functional-Handle

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, 2011BAE

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, 2011BAE

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

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 May 26, 2011BAE 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

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, 2011BAE

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, 2011BAE

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

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, 2011BAE

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

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

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

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, 2011BAE

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

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, 2011BAE

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, 2011BAE


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