maquette MOIS301E Reference number ISO 11783 13 2011(E) © ISO 2011 INTERNATIONAL STANDARD ISO 11783 13 Second edition 2011 04 01 Tractors and machinery for agriculture and forestry — Serial control an[.]
General message format
The general message format uses the parameter group number as a label for a group of parameters, with each parameter expressed as characters, scaled data within specified ranges, or bits Characters are transmitted starting with the left-most character, while multi-byte numerical parameters are transmitted with the least significant byte first For variable-length messages, those with eight or fewer data bytes are sent in a single CAN frame, whereas messages with nine or more bytes require the transport protocol (TP) per ISO 11783-3 or the extended transport protocol (ETP) per ISO 11783-6 When the message has fewer than eight data bytes, unused bytes are filled with FF16 values to maintain proper formatting.
File data format
Data
Data consists of a block of bytes (unsigned eight-bit values) All values in the range of 0 10 … 255 10 ,
00 16 … FF 16 are allowed There is no special handling of individual characters (control characters, end-of-line markers, end-of-file markers or similar characters).
Bit groups
Bits are packed into bytes, with one to eight bits organized from bit 7 to bit 0 For larger data groups of nine to 16 bits, two bytes are used, with the least significant byte (LSB) containing bits 7 to 0 and the most significant byte (MSB) containing bits 15 to 8 Unused bits within these groups default to a value of zero, ensuring data integrity and consistent formatting.
Integer
Unsigned 16 bit 2 bytes, LSB first 0 … 2 16 −1 0 10 … 65535 10 Unsigned 32 bit 4 bytes, LSB first 0 … 2 32 −1 0 10 … 4294967295 10 Signed 32 bit 4 bytes, LSB first, two's compliment −2 31 … 2 31 −1 −2147483648 10 … +2147483647 10
Character string
A string is composed of characters represented by bytes, each being an unsigned eight-bit value The length of the string is determined by a dedicated string length data item According to Annex A, only specific characters are permitted within strings used as filenames or path names, ensuring compatibility and security in file systems.
Data transmission control
General
Effective communication between clients and financial services (FS) begins with a client-initiated request and concludes with an FS response To ensure fail-safe and reliable interactions, clients must accurately associate received responses with their original requests Additionally, in case of errors, clients should resend requests without re-executing the entire process, preventing unnecessary duplication and maintaining transaction integrity.
Strategy
Communication failures between clients and the FS can occur due to transient issues, resulting in no response These failures may happen during the request message, when the FS does not receive the request, or during the response message, when the client does not receive the response Since the client cannot differentiate between these scenarios, it should repeat the request to ensure data retrieval.
Implementing a transaction strategy is essential to ensure reliable communication between clients and file servers (FS) Without a proper strategy, if the FS does not receive a request, the client may resend the request, prompting the FS to respond with the requested data However, if the client does not receive the correct response message and sends a second request, the FS automatically proceeds to send the next data in the file, as data requests are designed to advance to subsequent data segments This behavior highlights the importance of a robust transaction strategy to maintain data integrity and proper synchronization during data transfers.
A transaction strategy is therefore required to prevent such errors Each client on the network maintains its own transaction number (TAN) counter, which should start at 0 after a power cycle
Each client generates a Transaction Authentication Number (TAN) for every request sent to the Financial Server (FS) by incrementing the last TAN used, ensuring secure communication The client verifies that the response contains the same TAN used in the request to prevent lost commands and maintain session integrity The FS keeps track of the last processed command and response for each client by incrementing the TAN for subsequent requests When a new request arrives, the FS compares its TAN with the previous request's TAN from the same client; if they differ, it processes the request and sends the response; if they are the same, it retransmits the previous response without reprocessing This mechanism ensures accurate transaction handling, even if duplicate requests are received, by implementing or retransmitting responses accordingly.
Timeout
The execution time of all FS commands (the time between request and response) is maintained within reasonable limits The client shall monitor the time while waiting for a response
The timeouts specified in ISO 11783-3 for the transport protocol and in ISO 11783-6 for the extended transport protocol shall be met for the execution of commands
If a timeout expires, the request is assumed to have failed and the client shall repeat the request using the same TAN
If a request response exceeds 200 ms after the request is completed, the FS sends a status message to indicate a busy state to the client This mechanism ensures a request timeout of 600 ms if the FS does not display a busy status within that timeframe.
Date and time support
Several FS commands require a file date and time, which is always recorded in UTC The file server's real-time support can be implemented either by maintaining its own clock or by requesting time and date information through the Time/Date parameter group specified in ISO 11783-7 The file's date and time reflect the most recent modification, meaning it records the latest date and time when the file was modified Importantly, opening a file for read/write access without making any modifications does not update the file's timestamp.
Multi-client support
The file server shall support one or more clients If more than one client has a connection simultaneously, the
FS shall function with each client as if it is the only one on the network There shall be no interference between the commands processed for different clients
1) Coordinated universal time, or universal time, formerly known as Greenwich mean time (GMT)
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Upon connecting, a client is assigned the primary volume's root directory as its current directory in the FS file system; if no volumes exist, the current directory defaults to the volume list "\\" Clients must use appropriate commands like Change Directory or Open File to access specific files, while multiple clients sharing common files must synchronize their directory and file naming conventions to facilitate access To prevent unauthorized access to proprietary manufacturer files, a reserved directory name containing the manufacturer code, as specified by ISO 11783-5, is designated, following a specific manufacturer-specific naming convention.
The manufacturer-specific directory name follows the format MCMC0000, where "0000" is a four-digit manufacturer code in decimal with leading zeroes Clients must only use directory names containing their assigned manufacturer code as specified in their NAME field If a client attempts to access a file within a manufacturer directory using a mismatched manufacturer code, the file system will block access and generate an “access denied” error.
When a file server supports multiple volumes, it allows for the creation of manufacturer-specific directories on each volume, which should be positioned only at the root level The responsibility for creating these manufacturer-specific directories lies with the client, ensuring proper organization and management across all volumes This structure helps maintain consistency and simplifies access across different manufacturer directories within the file server.
File Handles
A File System (FS) can support multiple file Handles, enabling efficient management of open files Many FS commands involve creating or using file Handles, while some commands operate solely with folder or filenames Internally, when the FS creates a file Handle to process these commands, it increments the count of open files to accurately reflect its internal status This functionality is essential for maintaining proper file management and ensuring system stability.
Volumes
Different types of media (FLASH, removable media, ruggedized disk drives) can be assigned to different volumes
An FS can support multiple volumes It is also possible for an FS to list no volumes — for example, with uninitialized media or no device found
The list of volumes, specified by “\\”, is the highest layer (or base) of a directory structure
A specialized service tool for the FS enables the creation of volumes according to the specifications outlined in Annex C, Initialize Volume Request (C.5.2.2) While the default volume names are assigned by the FS, the FS can permit the service tool to specify custom names for these volumes, ensuring flexibility and adherence to naming conventions during volume initialization.
ISO 11783 does not specify the method by which the service tool selects media or volumes to initialize when they are not explicitly named and listed in the volume list "\\".
The file server manages filenames and path names, ensuring each character in the 8.3 naming convention is validated according to the subset of ISO/IEC 8859-1 specified in Table A.1, as detailed in section A.2 Only printable characters appear when filenames or paths are displayed to users Additionally, for case-insensitive file systems, the file system converts all lowercase characters to maintain consistency and ensure proper recognition.
File servers that do not support long filenames must use the traditional 8.3 filename format, which limits the filename to a maximum of eight characters, optionally followed by a dot and a three-character extension Conversely, file servers that support long filenames utilize the full filename and path as defined in section A.2, allowing for more descriptive and extended naming conventions Ensuring compatibility with different file server types is essential for proper file management and data access across systems.
Table A.1 — ISO Latin 1 character set
NOTE This information is given for reference; the following does not use all the available characters given here
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[ ] any of the characters in Table A.1, including none from the set (optional);
[A-B] defines an inclusive range from the first through the last;
\ escapes the following character, as in “\[”, which indicates a single left bracket, not the containment of a set;
{m} exactly m of the preceding set;
{m,n} from m up to and including n of the preceding set;
\xXX character code in hexadecimal notation where XX are two hexadecimal digits (\x20, for example, indicates character code 32, which is the space character)
Names can range from 1 to 254 characters in length, utilizing a specific character set The file systems detailed in Annex D were referenced to establish name restrictions, ensuring compatibility while minimizing feature loss This approach guarantees that names adhere to system limitations without compromising functionality or usability.
LongNameChar ::= any single character defined by Unicode/ISO/IEC 10646 except NUL, \, *, or ? WildCardChar ::= [ *? ] {1}
Filenames use the names defined in A.2.2.1
EXAMPLE Test, Test.txt, Test Filename.long.name (specifically a LongName)
Volumes use the names defined in A.2.2.1
EXAMPLE VOL_B, Flash Volume (specifically a LongName)
A path definition is similar to a filename definition but has additional prefix definitions and delimiters between path segments
When a directory listing from the path "\\" (two backslashes) is requested, the file system must return a list of available volumes All file servers should support the "\\" path syntax to enable clients to query volume information, including removable media, ensuring seamless access across different storage devices.
FS has only one volume
The two predefined special directory names, “.” and “ ”, refer to the current (“.”) and parent (“ ”) directories
These predefined directory names shall not be reported in a directory listing but may be used in a path name to specify reference to a current or parent directory
The tilde (~) character is commonly used as a placeholder for a manufacturer-specific client directory It can only be placed at the beginning of a path or immediately after a volume name When used in file paths, the tilde must be replaced by the corresponding directory to ensure proper access and functionality Understanding how to correctly use the tilde char is essential for managing file paths accurately in various systems.
FS utilizes the manufacturer-specific directory name on the current volume; if no current volume exists, the server’s primary volume is used The tilde ("~") can be included in the name but cannot be the sole character, as it is interpreted as the manufacturer-specific directory For example, “~\file1.txt” demonstrates proper usage of the tilde in file naming conventions.
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] {0,1} + [ + ] {0,n} ] | [ [ ] {0,1} + [ + ] {0,n} ] |
] {0,1} + [ + ] {0,n} ] | [ [ ] {0,1} + [ + ] {0,n} ] |
EXAMPLE 1 Path relative to current directory:
\Long path name\ (specifically a LongName) Path\
Long path name\ (specifically a LongName) EXAMPLE 2 Path relative to root of current volume:
\Long path name\ (specifically a LongName)
\\Flash Volume\Long path name\ (specifically a LongName) EXAMPLE 3 Path using manufacturer-specific folder indicator:
This path name includes as much path information as needed to produce an unambiguous specification of the path to the file:
EXAMPLE 1 Path relative to current directory:
Test.txt path\Test.txt Long path name\Test Filename.long.name (specifically a LongName)
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EXAMPLE 2 Path relative to root of current volume:
~\Level1\Level2\Test EXAMPLE 3 Path including volume:
\\Flash Volume\Long path name\Test Filename.long.name (specifically a LongName)
Figure A.1 illustrates a Filesystem (FS) architecture featuring volumes, directories, and files, along with an example path name The example path highlights a manufacturer-specific directory that is restricted for use by clients matching the designated manufacturer code in their NAME field This setup ensures secure and organized access within the FS, emphasizing the importance of manufacturer-specific directories for client compatibility and data integrity.
The wildcards “*” and “?” may be used:
⎯ “*” is a wildcard for 0 or more characters of a filename or folder name;
⎯ “?” is a wildcard for a single character in a filename or folder name Wildcards shall only be used for directory listings
EXAMPLE 1 Path relative to current directory:
~\?ath EXAMPLE 2 Path relative to root of current volume:
\\VOL_B\Level1\Level2\T?st.txt
\\Flash Volume\Long path name\Test ???? Name.long.name (specifically a LongName)
\\Flash Volume\Long path name\Test * Name.*.name (specifically a LongName)
\\Flash Volume\Long path name\T?st Filename.long.name (specifically a LongName)"
Figure A.1 shows an example of FS architecture with volumes, directories and files, and an example path name
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13 Figure A.1 — Example file server architecture
File server commands are divided into groups; four bits specify the group of the commands
Each FS command group has a number of functions The lower four bits of a command byte specify the function of the command
0 16 … F 16 Defined in each command message
The current status of the FS
The number of files that are currently open at the FS
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The number of the edition or version of ISO 11783-13 with which the FS or client is compliant
The Version Number parameter reported by the client should indicate the specific edition of the International Standard (ISO 11783) that the client is designed to support This parameter must remain unchanged during runtime, even when the client adapts to different file servers with lower versions For example, a Version 3 client will continue to report Version 3, even if it temporarily switches to Version 2 behavior to communicate with a Version 2 file server The File Server (FS) may display or log this information for diagnostics but must not reject communication requests based solely on the reported Version Number.
0 10 Draft edition of the International Standard
1 10 Final draft edition of the International Standard
2 10 First published edition of the International Standard
3 10 Second published edition of the International Standard
255 10 Compliant with Version 2 and prior (client only)
B.6 Maximum Number of Simultaneously Open Files
The maximum number of files that can be opened simultaneously at the FS
Data length: 1 byte Resolution: 1 bit Data Range: 0 10 … 255 10 (unsigned 8 bits)
0 1 File server supports multiple volumes
A number (TAN) assigned to a request so that the corresponding response can be identified
Data length: 1 byte Resolution: 1 bit Data Range: 0 to 255
In FS version 3 and later, if the response message from the server returns an error code other than 0 or 10 (indicating success), the subsequent parameters may contain invalid data and should be disregarded by the client The error code is a 1-byte value embedded within the response message, serving as a key indicator of the operation's success or failure Proper handling of this error code ensures reliable communication between the server and client, with error identification allowing for appropriate response to failed requests.
4 10 File, path or volume not found
8 10 Volume out of free space
10 10 Media is not present [formerly the code for error 13, below, in Version 2 FSs (see B.5)]
13 10 Volume is possibly not initialized
42 10 Invalid request length (used when the file pointer hits the start/top of the file or on invalid space request of the volume)
43 10 Out of memory (used by FS to indicate out of resources at this time and cannot complete request)
45 10 File pointer at end of file
The data object assigned by the FS and used by the FS and client to reference a file or directory for requested actions
0 10 … 254 10 Value of the Handle assigned by the FS for further access to a file
255 10 Error when assigning a Handle for a file
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The space in units of 512
Data length: 4 bytes Resolution: 1 bit Data Range: 0 10 … 4294967295 10 (unsigned 32 bits)
Number of characters in a path name This can be a volume, path, filename, wildcard, or combination thereof
Data length: 2 bytes Resolution: 1 bit Data Range: 0 10 … 65535 10 (unsigned 16 bits)
The allowed characters in a path name are specified in A.2.3.1
The data object used by a client to specify the mode of file or directory access requested
4 0 Open file for shared read access
1 Open file with exclusive access (fails if already open)
3 0 Open file for random access (file pointer set to the start of the file)
1 Open file for appending data to the end of the file (file pointer set to the end of the file)
2 0 Open an existing file (fails if non-existent file)
1 Create a new file and/or directories if not yet existing 1,0 00 Open file for reading only
01 Open file for writing only
10 Open file for reading and writing
When bits 1 and 0 are set for “Open directory,” bit 3 is ignored and treated as read-only, as it is used solely for querying the contents of the directory To access a directory, a path is created using the “Open directory” command, combined with the “Create a new file if not yet existing” option to ensure seamless file management and directory access.
The data object used by the FS to describe the file to the client
1 Volume is case-sensitive (Version 3 and later FS support this attribute)
5 0 Volume does not support long filenames
4 0 Handle does not specify a directory
3 0 Handle does not specify a volume
2 0 Volume does not support hidden attribute
1 Volume supports hidden attribute (Version 3 and later FS support this attribute)
1 0 “Hidden” attribute is not set
1 “Hidden” attribute is set (not applicable unless volume supports hidden attribute)
0 0 “Read-only” attribute is not set
1 “Read-only” attribute is set
The command from the client to the FS for setting or clearing file attributes
01 Set “hidden” attribute (not applicable unless volume supports hidden attribute)
11 Don't care, leave “hidden” attribute in current state 1,0 00 Clear “read-only” attribute
11 Don't care, leave “read-only” attribute in current state
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The position mode specifies the location from which the offset value is used to determine the file pointer position
0 10 From the beginning of the file
1 10 From the current pointer position
2 10 From the end of the file
The offset is used with the position mode to determine the file pointer position
Data length: 4 bytes Resolution: 1 bit Data Range: −2147483648 10 … +2147483647 10 (signed 32 bits)
The value of the file pointer position
Data length: 4 bytes Resolution: 1 bit Data Range: 0 10 … 4294967295 10 (unsigned 32 bits)
The number of bytes of data requested to be read from, or written to, a file, or the number of directory entries read from a directory
Data length: 2 bytes Resolution: 1 bit Data Range: 0 10 … 65535 10 (unsigned 16 bits)
Number of characters in a filename
For an FS without support for long filenames, the filename length is a maximum of 1 12 characters
For an FS with support for long filenames, the filename is a maximum of 1 254 characters (Version 2 and prior specified a maximum of 31 characters.)
The allowed characters in a filename are specified in A.2.2.2
The file date is represented by a bit group with the following 16 bits encoding
Bits 15 … 9 0 … 127 Year − 1980 (difference between the year and 1980)
If a file date is not available in an implementation, all bits are set to zero (0 10 = 0000 16 ) resulting in
The file time is represented by a bit group with the following 16 bits encoding
Bits 4 … 0 1 … 29 Seconds (in steps of 2 s)
If a file time is not available in an implementation, all bits are set to zero (0 10 = 0000 16 ) resulting in “00-00-00”
The number of bytes in a file
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2 0 “Recursive” mode is not set
1 0 “Force” mode is not set
0 0 “Copy” mode is not set
0 10 Do not report hidden files in a directory listing
1 10 Report hidden files in a directory listing
255 10 Parameter is not available, FS shall not report hidden files in a directory listing
The data object used by the client to specify the mode of volume access requested
1 0 Create volume using all available space
1 Create volume using space specified
0 0 Create a new volume if not yet existing (fails if existing volume)
The data object used by a client to specify the mode of the volume access requested A value of 00000000 requests the current status (This parameter applies for Version 3 and later FS.)
1 1 Request volume to prepare for removal
0 1 Report volume in use by client
0 Report volume not in use by client
The current status of the volume (This parameter applies for Version 3 and later FS.)
B.32 Maximum Time before Volume Removal
Maximum time a volume can be held off from being removed (This parameter applies for Version 3 and later FS.)
The allowed characters in a volume name are specified in A.2.2.3
B.34 Volume, Path, File and Wildcard Name
The allowed characters in a volume, path, file and wildcard name are specified in A.2.2.3, A.2.3.1, A.2.3.2 and A.2.3.3, respectively
The allowed characters in a volume, path and file name are specified in A.2.2.3, A.2.3.1 and A.2.3.2, respectively
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C.1 File server messages and data transfer
Two PGN (parameter group numbers) are reserved for the FS message protocol: a) File Server to Client
Transmission repetition rate: As required
PDU specific field: Destination address
Parameter group number: 43776 (AB00 16 ) b) Client to File Server
Transmission repetition rate: As required
PDU specific field: Destination address
Before establishing a connection with the file server, a client (ECU) can assess the server's capabilities by utilizing specific PGNs These PGNs facilitate the exchange of diagnostic and operational data, enabling efficient communication between the ECU and the file server for seamless data transfer.
FS utilizing the transport protocol specified in ISO 11783-3 or the extended transport protocol given in ISO 11783-6 Destination-specific messages shall be used and connection management implemented
The ECU client must wait for a response before sending additional commands, as a fixed timeout cannot be established due to varying response times for different commands Instead, clients can monitor the progress of FS command processing by utilizing the File Server Status message, ensuring efficient and synchronized communication.
The error code 12 10 , “Function not supported”, enables the FS to indicate to a client that a specific function is not supported All file servers shall implement the complete set of functions; nevertheless, an FS based on a certain revision of this part of ISO 11783 might support fewer functions in the case of the addition of new functions in a later revision Each unsupported function in the command group's directory handling, file access, file handling and volume handling shall obtain a response from an FS with the error code set to
“Function not supported” when the requested function is not available in the file server