Electrical Design Software

Use of electrical CAD software is driving productivity gains for panel builders, system integrators and end users by adding layers of intelligence to two-dimensional drawings.
By Renee Robbins, Control Engineering June 1, 2008
Test drive before you buy

Troy Schmidtke is passionate about software and the role it can play in a U.S. manufacturer’s competitiveness. His passion, however, is not focused on the massive business systems that take armies of consultants years to get running, but rather on a more precise, practical, and focused class of software that controls engineers may not be making the most of: electrical computer aided design (eCAD) software, part of the computer-aided engineering (CAE) software market.

Control Engineering June 2008 cover story
Control Engineering cover story, June 2008

“In what industry is the U.S. the undisputed world leader?” Schmidtke asks, rhetorically. “It’s software. So why aren’t we leading that trend here? Manufacturing alone is not enough anymore.” The true value add that U.S. manufacturers can offer comes from the capabilities and flexibilities they provide through smart use of software.

Schmidtke is CEO of Design Ready Controls (DRC) Inc., a Minneapolis, MN, original design manufacturer (ODM). ODMs help machine builders design and manufacture control panels, and they often operate as the control design and manufacturing extensions of their OEM customers. DRC started as a contract manufacturer, but, says Schmidtke, “we’re more and more software focused.”

Like many engineers designing the schematics for control cabinets, Schmidtke started out focused on physical controllers, wiring, and conduit. He and his engineers used a simple installation of AutoDesk’s AutoCAD to create, store and share circuit drawings electronically. Many engineers still use CAD software this way today, because it’s simple and familiar.

Users of electrical CAD software, however, can realize large productivity improvements over the use of basic CAD. Unlike standard CAD software, eCAD contains specialized functions, templates, and symbols that profoundly increase design efficiency, and eliminate the errors caused by repetitive manual tasks.

CAD vs. eCAD

To highlight the differences in eCAD software and traditional CAD, Autodesk conducted a productivity study that pitted AutoCAD (the company’s principal CAD software package) head-to-head against AutoCAD Electrical (an eCAD software package it acquired from VIA).

The study measured the time it took to perform 10 common controls tasks and found that eCAD software users performed consistently quicker. For example: creation of new designs was 84% faster; editing of existing designs was 77% faster. Creating panel layouts from an existing control schematic happened 61% faster. To complete all 10 tasks, users of AutoCAD software required 36 minutes, 52 seconds, while users of AutoCAD Electrical software required only 7 minutes, 37 seconds—an overall productivity gain of 80%. In addition, 30% fewer commands were required to complete the same tasks, thereby greatly reducing the risk of errors.

eCAD programs allow users to automatically generate electrical schematics. This saves time and also reduces errors because tasks like wire numbering and cross referencing are handled automatically. The software also lets user edit PLC data, export tags for a wire list, and create bills of materials (BOMs).

Since becoming aware of the advantages of eCAD, Schmidtke has worked with EPLAN Electric P8 and promise-e software packages. (Bentley Systems, Inc. in Exton, PA acquired Brookfield, WI-based ECT International, developer of promise-e, in January 2008. EPLAN Software & Services, a wholly owned subsidiary of enclosure manufacturer Rittal, is based in Monheim, Germany.)

“We like EPLAN,” says Schmidtke. “The Europeans are considerably farther ahead when it comes to eCAD, and they’re moving quickly. We like how EPLAN has been architected to a database. It’s very conducive to what we do.” EPLAN Electric P8, introduced in 2006, combined the technologies of EPLAN 21, an object-oriented system, and EPLAN 5, a graphics-oriented CAE tool, under one system.

In response to the capabilities of eCAD, DRC has introduced Automated Panel Expert (APE) software, a trademarked and copyrighted expert-system based tool that drives eCAD software. “APE is a configurator that runs in front of eCAD, taking advantage of eCAD’s abilities to set up queries and quickly generate a set of intelligent documents,” says Schmidtke.

While eCAD programs make computer-aided drawing software specific to electrical needs, the APE configurator automates design tasks based on specific industries, such as HVAC, water/wastewater, air filtration or energy.

Using EPLAN’s automated programming interface, APE is able to process an order and feed EPLAN Electric P8 a complete set of drafting instructions for each panel ordered. With this instruction set, and utilizing its own unique placeholder object and macro variant technology, EPLAN Electric P8 is able to pick, place, and size the necessary devices, component parts and wires into a set of as-built schematics and layouts. The software is subsequently used to diagnose the drawings for accuracy and generate manufacturing reports including as-built PDF schematics and machine tool instructions.

In previous generations of APE, says Schmidtke, many months of programming were required to create the engineering documentation required to build and wire the panels. Using eCAD software, DRC does not have to program individual aspects of a circuit, such as wire gauge and protection sizing. This can save significant time, and reduce errors.

Error-reduction evolution

“Error reduction features such as automatic wire connection, automatic wire numbering, and automatic cross referencing were available in the first versions [of EPLAN] created in 1984 to run on early x86 DOS computers,” says Oslem Falkiewicz, EPLAN marketing manager. Users were also able to manage parts and automatically generate BOMs, terminal diagrams, and cable diagrams for more efficient and accurate equipment installation.

eCAD’s early focus on documents and drawings has given way to a greater focus on database functionality and interoperability. Key features of eCAD software include the ability import and export drawings in a variety of file formats, the ability to track changes, and libraries of symbols and device data that can automatically populate a drawing. AutoCAD Electrical, for example, ships with more than 2,000 schematic symbols.

Bentley Systems Inc.’s promise-e works with SQL and Oracle database file formats to facilitate enterprise data management. It also includes built-in wizards to create symbols, macros, and database content. eCAD users “are computer literate but not necessarily computer geeks,” says Arthur Sawall, developer of promise-e and now vice president with Bentley Systems. “Therefore, eCAD vendors need to take the graphical object from the component manufacturers and link it to a record in the database, such as connection points, and give it a device tag.”

Sawall says promise-e has symbol libraries and components from several major automation providers, including Rockwell Automation, Siemens, Eaton, Modicon, GE, Panduit, Weidmüller, and others.

EPLAN also has tested and certified device data created in collaboration with component manufacturers. Available via Data Portal, a Web-based repository, are macros of sub-circuits, assembly drawings, function templates for an intelligent device selection, international designations, preview images, and manuals.

Using such symbol libraries and pre-built macros “not only makes searching individual manufacturer catalogues unnecessary, it also eliminates the need to type in part numbers or create one’s own macros,” says Falkiewicz. “The time allocated to these fishing expeditions for the right components is instead turned into productive work time.”

The ability to track changes to a design made by a customer or other collaborative partner is another key benefit of eCAD software. To handle such transfers and tracking, AutoCAD Electrical compares previously exported DWG files with the original so that an exception report can be generated.

promise-e contains all data in a DWG file, as well as in an SQL or Oracle file. “Because we have a database, we have a data editor. This means I can open the editor, which looks like a spreadsheet, and I can update the data and have it automatically update the schematics,” says Sawall.

EPLAN’s redlining function allows all documentation to be converted to PDF format and subsequently made available for review and modification.

Companies that export designs for global assembly face an array of regulations, and eCAD software can help by standardizing documentation and automatically translating languages.

General Motors, for example, addressed this concern in 2006 when it announced plans to unify its various CAE tools throughout Europe, Asia, and the U.S. under one global standard, EPLAN Electric P8. For GM, this provided the opportunity to standardize its engineering across geographies. GM plants in various countries now can work on the same project in their respective languages, with automatic conversion to the preferred symbol representation of their country.

At Honeywell Process Solutions, engineer, procure, and construct (EPC) contractors like Fluor will dictate the formats that they want for electrical documentation, says Matt Willmott, a 16-year veteran of the project engineering services arm of Honeywell. A typical milestone for these system integration projects is delivery of design documentation. Willmott says that such requirements are leading Honeywell to move away from general CAD software and toward the use of a data-driven tool for electrical design documentation, E3.schematic from CIM-Team/Zuken.

Honeywell has developed a customized software package called Drawing Generator on top of the E3.series tools to execute the design and implementation of safety and control systems globally. A library of Honeywell objects are being developed to further increase productivity through design reuse and standardization, says Willmott.

Intelligent three-dimensional drawings are the next frontier of design software, and a number of eCAD vendors have expanded into 3D plant design tools so engineers can work in the same environment to create things like piping and instrumentation device (P&ID) diagrams. The latest E3.Series software version, for example, lets users output panel data into STEP AP203/214 format. This enables transfer of design data to create three-dimensional models in 3D mechanical CAD environments.

Bentley Systems commissioned a 2008 study that compared use of 3D design tools to 2D tools. The study found that productivity with 3D tools for overall plant design increased by at least 15% for more than 70% of study participants. Personal productivity increased at least 50% for more than half of participants.

Because electrical schematics are, by nature, two-dimensional drawings, 3D technology may not be important to eCAD users. But the integration of electrical controls design data with other digital manufacturing software is likely to continue, as reuse of data continues to drive productivity improvement.

Author Information
Renee Robbins is senior editor with Control Engineering. She can be reached at renee.robbins@reedbusiness.com .

Test drive before you buy

All electrical CAD software packages can help save time versus the process of manually drawing electrical schematics or using standard CAD packages to draw your panel layouts. Prices vary widely, but so does functionality. Check what’s included in a package, and which ones requires add-on modules. Also ask what your customers or suppliers what they are using. Interoperability is common, but some data exchange methods are easier than others. Visit company Websites to see product demos, sample schematics, and system details. Many vendors also provide demo CDs and/or trial versions of their software so you can see how it applies to your specific project.

AutoCAD Electrical


EPLAN Electric P8

EPLAN Software and Services Gmbh & Co.

promise-e 2007

Bentley Systems Inc.



Engineering Base


PCschematic ELautomation

DpS CAD-center ApS

Electrical Design Suite

SCADA Systems Ltd.

Electra 2005

Radica Software

Want this article on your website? Click here to sign up for a free account in ContentStream® and make that happen.