ROBUST ELECTRONIC DESIGN
Electronic Equipment
John R. Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE
June 11, 2004
jrbarnes@iglou.com
Companies and organizations develop equipment for their internal use,
typically to:
- Help develop products.
- Exercise prototypes to prove that they meet the company's standards and
applicable national/ international standards.
- Stress-test prototypes to prove that they have sufficient design margin,
for economical manufacturing and reliable operation in the field.
- Manufacture/test/repair the products or critical subassemblies.
- Diagnose problems in the field.
The design requirements for equipment tend to be moving targets, constantly
evolving as the associated product(s) are tweaked, enhanced, and redesigned:
- Progressing through development.
- Accumulating manufacturing experience.
- Receiving feedback from users and Field Service.
Because we usually build only one or a few copies of each piece of equipment,
we can afford to build in some extra capabilities up front to cover the
uncertainties associated with the project. For accurate measurements we want
the equipment to be at least 3 to 10 times as accurate as the parameters we
are trying to measure. A well-integrated development environment with
powerful debugging tools can greatly reduce programming time, even if the
resulting code is somewhat inefficient. To keep from slowing down development
by running into artificial limits, we usually want to provide for:
- 10 to 20% more input/output points than we expect to need.
- Twice as much code, data, and stack memory as we expect to need.
- Twice the processor speed as we expect to need.
The safety requirements for equipment are usually based on the company's/
organization's internal standards and voluntary industry standards. Since we
control the equipment, who uses it, and when/ where/ how it is used, we can
provide safe working conditions by a combination of:
- The inherent design of the equipment and process.
- Guards over dangerous subsystems.
- Warning labels.
- Operator training.
- Personal protective equipment.
- Special tools.
- Proper operating and maintenance procedures.
- Controlling the environment around the equipment, including power
quality, taking precautions against electrostatic discharge (ESD), and
keeping interfering devices well away from the equipment.
We can get by with fairly skimpy parts/ materials specifications for
equipment, because we usually buy enough for the life of the program in one
lot. Similarly, the manufacturing/ test documentation for equipment may be
sparce, perhaps some sketches and an engineering notebook, because most of
the assembly and debugging will be done under the direct supervision of the
equipment designer. Repair and service documentation should be fairly
complete, because the equipment designer may not be available when they are
needed.
Because of the small quantities needed, we will usually be limited to
off-the-shelf power supplies or product power supplies for equipment. Moving
equipment to another country may require redoing some of the primary wiring:
- Changing line cords.
- Changing input connections to power supplies.
- Adding a step-up/step-down power transformer.
Flexibility tends to be more important than an "optimum" design, letting us
develop electronic equipment quickly while holding down the engineering and
programming costs. In many cases we will adapt/ enhance a previous design
instead of doing a new design from scratch. We also tend to be very
conservative in our design and selection of subsystems, parts, and materials,
to minimize the risks associated with the project. In general, we want to
limit our custom development of equipment to:
- Adapters to mate general-purpose equipment to our product(s).
- Special requirements that can't be met by off-the-shelf equipment.
Robust Electronic Design, Inc.
is the research arm of
dBi Corporation,
an A2LA-accredited EMC/EMI/ESD testing and
consulting company based in Lexington, Kentucky. Our staff has been directly
involved in putting over 115 major electronic products into mass production at
Sycor, IBM, and
Lexmark, as well as doing the EMC/
EMI/ ESD engineering tests and FCC/ CE-Mark approval tests for over 70 products
and testers developed by clients--bringing them into compliance with both
domestic and international laws and standards. Our staff has also served as
expert witnesses in two lawsuits, one involving a personal-injury case, and
the other involving semiconductor patent law. We have over 31 years
experience in the computer and electronics industries developing electronic
products and electronic equipment that:
- Work.
- Are safe and reliable.
- Can be manufactured, tested, repaired, and serviced economically.
- May be sold and used worldwide.
- Can be easily adapted/enhanced to meet new and changing requirements.
Our President, John R. Barnes, is a Professional Engineer licensed in the
state of Kentucky, a NARTE-Certified
Electromagnetic Compatibility Engineer, a
NARTE-Certified Electrostatic Discharge Control Engineer, a Senior Member
of the IEEE, and an
Advanced-class amateur radio operator. He has written three books,
Electronic System Design: Interference and Noise Control Techniques,
that was published in English and Russian, and Robust Electronic Design
Reference Book, Volumes 1 and 2, which came out in March 2004. He has
also written articles on designing electronics for electrostatic discharge
(ESD) immunity for
Printed Circuit Design and
Conformity magazines.
Robust Electronic Design, Inc. and dBi Corporation may be
contacted by:
- E-mail at
jrbarnes@iglou.com
- Fax at (859)252-6128.
- Phone at (859)253-1178.
- Snail-mail at 216 Hillsboro Ave, Lexington, KY 40511-2105.
Last revised June 11, 2004.
