The promise of an integrated product lifecycle environment has energised many companies to invest in solutions from mainline product lifecycle management (PLM). Analysis of these solutions shows a principle focus on the close integration of mechanical product development within the lifecycle environment.

Electromechanical components and related wiring are an important element in many products. Cars will not operate without electrics and cranes cannot lift without control circuitry. But the perceived importance of electromechanical design is low. This relegates electrical engineers to accept solutions that are no more than glorified drafting tools. Increasing customer demands consistently challenges software authors to deliver improved capability and value.

Innovation is driving ET tools

The values of software automation in electrotechnical (ET) design are too often misunderstood. To increase the value of these technologies in the overall design and product environment requires a change in customer awareness linked to innovative new product capabilities. Many applications in this market exist as add-ons to 2D drafting systems which tends to perpetuate the common perceptions of drafting, rather than design, automation. Many products provide innovative capabilities that address the design challenges facing electromechanical engineers head on. Delivering improved productivity, product quality and, more importantly, integration into the design through manufacturing and service processes.

Ease of use encourages productivity

A number of solutions use platforms such as AutoCAD as the graphics interface to their design applications. Other developers provide Windows native solutions. Whereas Windows native solutions provide users with a more consistent integrated look and feel, add-on applications have the additional benefit of being able to take advantage of the underlying CAD application for more advanced drawing and detailing.

Project management is critical

Most solutions provide the ability to partition designs into hierarchical project tasks, but very few allow true multi-user concurrent design, useful, if not essential, in larger projects. Many projects include external referenced information. Examples of these would be spreadsheets, drawings and Microsoft Word documents. A number of products also allow for external documents to be integrated and referenced in project documentation. Configuration management tasks, often vital for ensuring valid use and re-use of information, are generally accomplished through in-house or third party add-ons.

Increasing trends in subcontractor collaboration and wider use of the internet require more controlled access to information and improved management of design information. Many solutions allow export to web enabled drawings covering schematics, wiring and panel diagrams. Controlling data over the extended enterprise often requires more intimate integration with third party PLM solutions. These integrations are often limited in their capabilities, requiring users to make do with less than satisfactory interfaces, and often require manual intervention.

Manufacturing links

Embedding manufacturability rules into the design process increases quality and performance. This eliminates downstream overheads by validating fundamental design constraints, such as short circuit checking and contact to coil usage, at the earliest instance. More advanced solutions further improve user productivity by providing design advisory functionality. As an example, users may be only be offered a limited selection of parts for designs. These would be selected by the system based on current valid design parameters. Basic features such as automatic wire and part numbering are common, and many products allow the user to define individual wire and part naming conventions for global and individual application.

ET design - variations on a theme

Electrotechnical design solutions exist to service a number of different requirements, with a common theme. Wiring constitutes the principle interconnect medium. These generally encompass:

" High voltage designs used in applications such as power and sub-station design;
" Interconnecting components such as relays, PLC's and fuses, together with sensors, actuators and indicators generally found in machine design and industrial control circuitry;
" Wiring looms and harnesses used extensively in markets such as automotive, locomotive and aerospace application. Electronic circuit interconnect for consumer goods, IT products and telecommunications application.

We will exclude comment on high voltage design, used within companies such as Mitsubishi Electric, GE and Alstom. Although this is an important market, for the purposes of this discussion we will focus on products that require intimate integration within mechanical structures and assemblies, such as cranes, cars, washing machines and photocopiers. Namely control panel and wire harness design

Control Panel Design

Many integrated design applications provide the ability to move seamlessly between schematic design and control panel layout environments. This improves product quality and reduces development effort. These solutions also aim to automate much of the documentation and information preparation required by manufacturing and service operations. More advanced products offer automated part placement and auto-routing of wires through panel ducting. In the E3.Series product from CIM-Team in Germany, schematics and panels exist as multiple views on a single data structure. Additions or modifications to circuitry, parts or wires in the physical panel or schematic automatically reflect throughout the design as changes are made. This ensures consistency between schematics and physical panels, and reduces the effort required to validate designs through the development process.

Wire Harness Design

Significant inroads are being made in the area of wire harnessing. Mainline CAD vendors provide differing levels of capability for wiring design within their portfolios. These solutions generally integrate with their 3D CAD products to allow for 3D wire harnessing in mechanical structures. Although capable, these solutions tend to focus on the needs of the 3D developers, not the electrical engineer. More recently, mainstream CAD vendor Autodesk has invested in electrical design and harnessing solutions. The fruits of these acquisitions should become more apparent in future releases of Autodesk's Inventor products. A number of electronic design automation (EDA) software providers also provide capable harnessing solutions. Mentor Graphics' recently acquired solutions from Harness Software and Innoveda allow them to broaden their solution coverage for harness designers and manufacturers.

Wire harness solutions aim to improve productivity through the design to manufacture and assembly process. In addition, significant benefits are often realised in downstream operations such as after sales service. As is common in other electrical schematic design disciplines, products generally encompass logical schematics and physical design. In the case of a harness, the physical representation exists as a 2D form board document. Form board layout is often produced in conjunction with a 3D modelling application. This allows users to develop wire length and bend characteristics within the physical design, for instance a car. These solutions generally manage documentation used within manufacturing, producing connector information, shielding and termination details.

Although some harness designs can be accomplished with standard control system design software, features in these systems are often too manual to benefit sophisticated harnessing requirements. Common harnessing features include management of design variants, connector, cables, bundles, manufacturing data and extended service information. Whilst some vendors cite automation and intelligent integration with electromechanical and digital infrastructure as key solution benefits, others focus on simulation. This enables users to validate operations and to provide in-service testability information. New entrants in this market have taken advantage of the opportunity to develop specialist applications that deliver unique capability for harnessing designers. As an example, First Earth, a small developer in the UK, has focused on developing products that will detect potential failures and sneak paths within designs.

Efficient Storage and reuse of Information

Most products store commonly used elements for re-use in subsequent projects. Often based on standard database technology this repository often includes circuitry, wires, cables and non-drawn items, for example fuse wire or connector fittings. Most solutions provide extensive access to design information for use in downstream applications documentation. Many vendors provide the facility to customise outputs to suit common requirements to deliver manufacturing information, including parts and wiring lists. For more advanced output, drawings and database information can be exported and manipulated by external applications to obtain the necessary information. To enable more sophisticated integrations some applications provide bidirectional access to drawings and databases.

Automating Design and Sales Processes

Within control systems and harness markets, there is a strong driver to improve the sales process and order - to - delivery efficiency. To increase design productivity, some software vendors provide facilities to develop product variants with a single design master. This facility is less common within the control panel software market, but is common in wire harnessing solutions. Design re-use is common. Most products allow for circuit, drawing and part information to be stored for later re-use and, automatically apply routine checks to ensure that re-used data remains valid. Up-front costing and proposal generation can be improved by re-using common stored modules, and by automating key stages in the design and manufacturing process. Although a number of products provide this facility, this is often accomplished with some manual effort or additional programming. A number of software companies enable automatic design functionality and document generation by providing programmable access to stored drawings, common functions and database information. This allows companies to reduce bid and design cycle times and lower engineering overheads.

In conclusion

Control systems and harness design solutions have evolved to enable increased productivity and quality, while encouraging design automation and streamlining the order - to - manufacture process. What were once simple drafting aids now provide valuable design assistance and encourage product validation. By taking advantage of these solutions, companies are more able to improve product capability, quality and process performance. Integrating these solutions within the product lifecycle environment improves responsiveness and, ultimately, profitability.

Allan Behrens

First appeared in the EA Report, Expert's View, October 2003

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