WSCAD into VNS

The Standard DIN V40950 ‘Neutral interchange format for diagram data’  was drawn up with the participation of many large companies with the aim of facilitating the transfer of data between widely differing CAD programs.  A further, and im­portant aim of VNS is the archiving of circuit diagram data in a form which is independent of manufacturers.  One outcome was the fact that the format could not be defined too strictly, so that each CAD manufacturer could introduce the specific character­istics of his program into the process.  Thus a detailed knowl­edge of both the source and the target system is needed, if a conversion via VNS is to be successful.  Certainly the capabili­ties of level 1 are still limited, so one should not expect to be able to continue in the target system without doing some re­working.

In the meantime we have Version 2.0 of this interface specifica­tion, which controls the exchange not only of charts (documentation) but of all the data associated with a project.  This does however considerably increase the required process­ing time.

During the transfer process, temporary files ‘*.TPL’ or ‘*.TSY’ are created.  If an error occurs the VNS write-processor gives an appropriate error message.  You can then use the temporary files to find the source of the error in the project. 

During the transfer process, the whole drawing set is converted into two ASCII files.  These files, with the extension ‘.VPL’ and ‘.VSY’ are stored in the same directory as the files of the current drawing set.  Both files are ASCII files, which can be manipu­lated with any normal editor.  In the ‘.VSY file’ (symbol file) are the symbol definitions and in the ‘.VPL’ file (connection file) are the call commands for the symbols, the electrical con­nections, texts and free graphics.  For the transfer process, project data is required (the so-called header data), which WSCAD 5 cannot automatically take from the circuit dia­gram (drawing number, sender etc.).  You are prompted for these after the conversion process has started and then have to enter them.  The configuration of the VNS interface enables you to control the transfer of the component-related texts (e.g. func­tion text).

For those familiar with the VNS standard, the important features of the WSCAD conversion are summed up below in note form:

• As WSCAD 5 does not recognise a drawing frame as a separate element (the frame is more usually produced in ‘Draw’  mode), the necessary symbol for the DF (drawing frame) set is automatically generated, but is marked as invisible.

• In the case of the SD (symbol definition) data set, the component type is transferred as symbol form.  The admissible values are:  (STANDARD, SPULE, KONTAKT, SPIEGEL, KAMM, HAUPTELEMENT, NEBENELEMENT,KLEMME,KABELADER).

• In the case of terminals, the designation of the internal side is transferred with an SA data set, which follows the symbol definition.  Here the ‘RICHT’ sign is defined, and the value can be 'OBEN', 'UNTEN, 'LINKS' or 'RECHTS'.

• Using the line types defined by V40950, WSCAD recog­nises four further types which are transferred with the identification numbers 5 to 8.

• WSCAD supports two features of a connection point: the pin number and the pin name.  If the connection of a sym­bol only has one of the two, the value (pin number or pin name) is transferred by means of a TA set and a ‘:’-attrib­ute according to the semantic table.  If both features are present, the pin number is transferred as a TA set and the pin name is transferred as an AT set.

Hint

The wording for the SA and SD data set has been kept to German words, because the VNS is a German standard and is mainly supported by German CAD software)