VUTRAX Application: Defence

VUTRAX helps Pascall fight for peace dividend

VUTRAX has been used by Pascall Electronics Ltd. of Ryde since 1986, when it was (according to Hugh Grayson, Chief Draftsman) "The only system we could find which adequately catered for surface mount technologies."

Pascall Electronics is a leading independent British manufacturer in the military electronics sector. Its work covers three main areas:

• Switch mode power supply design, covering all types of aircraft, missiles and tanks, including the British Army Warrior armoured vehicle.
• Logarithmic amplifiers, which are used in early warning radar and weather radar.
• Satellite carrier monitoring equipment, used for measuring the power of incoming satellite signals. Unique to Pascall, these products are found at the rear of telecommunications dishes at earth stations.

The company begins most projects with mechanical design. As Hugh Grayson explains, "Normally we begin with a mechanical file, get an idea of the shape of the PCB, design the PCB and finally make what compromises are necessary between electronic and mechanical design. Sometimes some of the mechanics require a casting and this makes it essential that we get the designs right first time.

This ECAD package has strong mechanical design capabilities ...more than adequate for Pascall's needs, adds Hugh Grayson. "It is a very good 2D drawing system. Very user friendly." Thus despite enough mechanical work to keep a draftsman occupied for 90% of his time, there are no specialised mechanical CAD systems found in the drawing office.

PCB work is divided between the remaining designers, who work in tandem with the mechanical draftsman on all projects. According to Nick Jay, a significant benefit of the VUTRAX software is "the ability to rat's nest, top-down modify and then rat's nest again ...and the reassurance this gives designers."

With the rat's nest generator, connection data, library data and track widths are processed and various checks performed. Gates used on the schematic are packaged into physical devices on the PCB. From this information the system creates a Rat's Nest (a screen display of all the components in a `tray', with point-to point connections between them).

The top-down modify procedure means that fundamental changes to the electronics that are initiated on the schematic are reflected at any stage into the current artwork. Deleted nets can still be used as templates for new routes or plotted as part of a salvage scheme for on-site service.

Hugh Grayson also highlights the value of a mass edit facility. This feature allows global changes (or where necessary, deletions), including point types, layers, track widths and pad sizes.

Efficient design has been at the heart of Pascall Electronic's success to date. The company is now carrying its expertise into new markets and new applications, emphasising again the importance of flexible and powerful electronic and mechanical design facilities. VUTRAX continues to match these requirements.