ENGDAT

ENGDAT is a specification, for use primarily within the automotive industry, describing how CAD/CAM files and other engineering data can be transferred electronically between two parties.

Each ENGDAT transmission consists of a single EDI message and one or more CAD/CAM files.

The EDI message is used to describe the files within the exchange, their format, generating system and any drawings contained within each file.

This allows a group or ‘folder’ of information to be transmitted between trading partners. The folder may contain a number of different files, each containing technical engineering data such as CAD/CAM drawings. These files may be in any of a number of different formats, and may have been generated by a variety of applications.

An ENGDAT package is the set of data files to be sent using an ENGDAT message i.e. the EDI message itself and all engineering data files linked to the message.

The ENGDAT Message

The ENGDAT v2 message contains information required to interpret and use the engineering data, but does not contain the engineering data itself. It contains a reference to and a description of each engineering file being sent.

The engineering files are sent as separate files from the EDI message, but within the same communications session.

The ENGDAT message itself is a ‘header’ – it describes the contents of the folder in detail.

Contained within this message header is information about the folder and the individual files within it. This includes:

The exchange reference number – a unique 17-character alphanumeric reference that uniquely identifies the folder
For each of the files within the folder, the file name, the format and version, the system which was used to generate the file and the date and time are stored. A file can be the actual drawing but can also include accompanying files, such as text files
Information regarding the group of engineering files i.e. the folder. The ENGDAT message stores details such as the origin and destination of the folder, the Exchange Reference Number, and the date and time the folder was created.
Information regarding documents that can be related to the folder. For each document, a document name and number, date and time are stored. Each folder can have many related documents.
Information regarding each drawing within a file. This includes a drawing reference number and name, description, engineering change numbers, etc.

Example of an ENGDAT Folder

Each ENGDAT folder consists of one or more files. These files may be CAD/CAM data files of any format, text files produced by a word-processor, or any other computer-generated file. In addition to these files, a header (the ENGDAT message itself) is also attached to the folder. The ENGDAT message contains descriptions of the folder, each file within the folder, and any drawings that may be contained in the files.

An example ENGDAT folder is described below:

File 1 ENGDAT EDI File – Header.

File 2 CAD File, containing a drawing of part number 23560.

File 3 Formatted text file generated by a word processor, describing changes to part number 23560.

File 4 CAD File, containing 3 drawings of a proposed new part.

Files 2, 3 and 4 were generated by various applications such as CAD / drawing applications and word processors. File 1 is the ENGDAT EDI file itself - this contains detailed information regarding the other three files, so they may be interpreted by the recipient of the folder.

Virtual File Name

The Virtual File Name (VFN) is used when transmitting ENGDAT information, to link together the multiple files that may make up the ENGDAT folder. The structure of the 26-character VFN is shown below:

Characters 1 to 3 - The text 'ENG', to identify this file as a member of an ENGDAT folder
Characters 4 to 20 - Exchange reference number of the folder
Characters 21 to 23 - Total number of files within the folder (including the ENGDAT header)
Characters 24 to 26 - Sequence number of this file within the folder (the ENGDAT header is always sequence number 1)

Example of virtual filename structure

This is an example of three CAD-files; two in neutral format and one in native format.

The ENGDAT message describes how to manage these CAD-files and the content of the files. The exchange reference number in this case is 98316.

Note that the zeroes before the exchange reference keep the positioning within the filename correct. The same rule applies to the handling of {No. files} and {File No.}.

ENG{Exchange ref}{No. files}{File No.}

ENG00000000000098316004001 (ENGDAT message)

ENG00000000000098316004002 (VDAFS-file)

ENG00000000000098316004003 (SET-file)

ENG00000000000098316004004 (NATIVE-file)

ENGDAT v3

ENGDAT v2 is a standard EDI message developed by ODETTE. ENGDAT v3, which is still under development, includes an XML definition of the message.

ENGDAT v3 has been developed under the auspices of SASIG (Strategic Automotive Standards Industry Group). Although ENGDAT v3 is currently in use, there are still various outstanding issues to be resolved.

Migration to a JADM (Joint Automotive Data Model) compliant message is planned for ENGDAT v4, which will be developed at a future date. This will include some editorial changes but no changes of functionality.

The official name of the ENGDAT v3 document is:

SASIG – Exchange and Management of Technical Data Guideline (ENGDAT v3 Rev.1)

An ENGDAT v3 XSD schema has been published and is available from the VDA or Odette web pages.

To differentiate the new ENGDAT version from the earlier versions, the use of "EN3" (for ENGDAT v3) as a message identifier instead of ENG (ENGDAT v1 and v2) has been agreed, at least for the European region. This means there is no need to analyse the message-file to detect what version of ENGDAT has been received, which is very helpful while both ENGDAT versions are in use.

ENGPART

ENGPART is a means of exchanging parameters that are relevant to the exchange of ENGDAT files, thus providing a partner profile description.

The ENGPART file is a machine-readable flat file in which data element codes, descriptions and values are separated by delimiters.

The ENGPART parameter file is normally transferred with an ENGDAT message, in the form of an ENGDAT package.

Its main purpose is to avoid oral and written communication of the partner profile information.

The information provided by one trading partner to another in an ENGPART file includes:

All the entities involved in the data interchange (departments and contacts) and the parameters needed for the exchange
All recipients who should receive data from the corresponding partner
All network parameters
Relevant parameters of applications used (application systems, formats etc)