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Designing a
TEST PLAN
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A test plan will save you time and money by focusing on compliance goals.
EMC Technologies can help you in this process with advice on
any test issue, from the test layout to navigating the compliance maze that you will face if you want to
export into the European and North American markets.
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EMC Technologies has unparalleled experience in providing compliance services for Australian
and South East Asian manufacturers exporting into the European and North American markets. |
We understand the subtleties and unique requirements involved in providing compliance information
for products destined for all major world markets.
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You want to sell your product in Australia and New Zealand? Again,
you've come to the right place. EMC Technologies has years of experience in providing a total compliance service
for products marketed locally. |
WE'RE NOT...............TALK TO US!
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Test Plan Design Process
The creation of a Test Plan is a 4 stage process:
1. Determine which standard applies to your product
2. Determine the performance criteria that apply to your product
3. Generate a Draft Test Plan
4. Generate a Final Test Plan
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1. Determine which standard applies to your product
The standard that applies to your product is determined by three main factors:
- the product family that your product belongs to (ISM, telecomms etc)
- the type of environment that your product will be used in (light/heavy industrial, domestic...)
- the export markets that you intend to target (New Zealand, North America, Europe...)
We suggest that you compose a Preliminary Check List including the above points and possible future markets. This will help you to maximise the value of your testing as your marketing strategy may be modified in the near future, requiring further testing to qualify for entry into other markets. Minor modification of your testing schedule can enable you to cover as many markets as possible.
To assist you in identifying the appropriate standard, we've reprinted an article by our
Technical Director Chris Zombolas, Choosing the Correct Standard.
DESIGN CONTENTS
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2. Determine the performance criteria that apply to your product
For Immunity Testing, your products response to a disturbance signal can be described as conforming to a certain performance level
similar to the following scheme. Alternatively, you can propose an alternative description of performance acceptable to you and your customer.
A generally accepted 4 level description of performance criteria is as follows:
- A No effect on the EUT (Equipment Under Test).
- B EUT function affected by disturbance signal, but self-recovers immediately
- C EUT function interrupted, user intervention such as manual reset required
- D EUT is damaged by disturbance signal and cannot recover normal function
It is your responsibility to determine the Pass/Fail criteria. You must bear in mind the implications of a failure of your device on your customer. What in one situation may be a minor inconvenience, in another may be life threatening.
Hence manufacturers of medical devices must be stricter in their application of Pass/Fail criteria compared to manufacturers of less
critical equipment. We are happy to consult with you in the determination of your Pass/Fail criteria. You may be able to consult with your customer on this issue.
DESIGN CONTENTS
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3. Generate a Draft Test Plan
IDEALLY we have been involved in the development of your product from the early
design stages. You've applied our recommended EMI/EMC optimisation strategies from the
board level up, and the structure of the Test Plan reflects our familiarity with your product and
your growing knowledge of the role of EMI/EMC within the wider scope of your product's
development plan.
Some of the issues you must address before finalising the Test Plan include:
- Is your product a system, an add-on, or stand alone? System components may have to be tested separately, or altogether, depending upon their size, interoperability and physical complexity
- Does your product require other equipment to function that the customer will supply and over which you exercise no control? If for instance your product is a card to be inserted into a computer, judicious selection of the test-bed computer is essential; a noisy computer will cause you to fail emissions and immunity testing. You would be well advised to procure a compliant computer for testing
- Will your product require immunity testing? If so, determine the levels of disturbance signal that your product must withstand so that you can design to a target...there's no need to build a tank if you don't have to. By the same token, be aware
of the price to be paid for cutting corners with low headroom design - unreliability in the field can quickly destroy your products reputation.
- Can you establish a normal operating mode for testing? It is essential that you exercise all operating modes to ensure a valid test, and strive to minimise the cycle time for these tests so that test time is reasonable. There is always a trade off between
test times and reasonable cycling of test sequences for multi-mode devices. Remember that testing under 'normal operating conditions' is the goal - aim to cover all major modes of operation but don't get carried away when designing your device test software
so that testing times become ridiculously long. For instance a radiated immunity test from 80MHz to 1000MHz with 1% frequency increments may require unreasonable dwell times if your test cycle time is too long. When in doubt, ask us!
- What system parameters can we monitor to assess normal device function, sub-system errors or system/module failures during immunity testing? We can provide remote video monitoring of control panels, or maybe you can supply filtered cable access to critical sytem parameters that can be passed out of the test chamber to a monitoring panel. The test integrity is much greater when filtered bulkhead connector penetrations are supplied to connect support equipment.
- Have you written test software to cycle your product through all its operating modes and record errors when testing?
As mentioned above, all modes must be exercised - if you can provide remote error monitoring at the same time, such as via a laptop
computer test monitor connected to a maintenance/configuration port on your device, test times can be optimised and test validity increased.
We've made a sample draft test plan available to give you some idea of what is required.
DESIGN CONTENTS
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4. Generate a Final Test Plan
When you have compiled your draft test plan, it is advisable that you consult with us so that the viability of tests can be verified. Sometimes the time required to cycle through a complete set of functional modes can be prohibitive. We have encountered test plans that would have required years to complete.
Other issues that can be addressed at this stage include optimum monitoring techniques, special bulkhead penetrations, construction of test jigs that best reflect final installations, construction of test cables of optimum length and shielding performance to maximise test performance. (The value of good quality and correctly assembled cable connectors cannot be emphasised enough. Blue-tacking a drain wire to an
aluminum shell might tickle your fancy at 2.00am on the morning of your test when you're struggling to get the test model ready, but it'll only waste time and money in the long run. Address shielding early and thoroughly...the aim is to be bored as your prototype sails painlessly through the test).
Remember that a couple of hours consultation at this stage can save many hours of set up time and improve initial performance so that modifications at test time can be
minimised.
DESIGN CONTENTS
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- The time you spend RESEARCHING AND DESIGNING your test plan before you present your product for testing will SAVE YOU MONEY...
- READ! (we can recommend titles; also check our BOOK LIST)
- ANTICIPATE where your product may FAIL and DEVELOP STRATEGIES to address potential problems
(this also encourages INFORMED DESIGN/REDESIGN on new products)
- Ask us QUESTIONS!!
On complex projects it pays to consult closely with us as early in the process as possible when designing your plan as there may be test setup issues (mounting modules, jig manufacture, support equipment etc) that have to be considered as part of the test validity - the standards can be a limiting factor and can specify minimum physical requirements (cable lengths, floor vs desk mounting...) Ask first, or you may find yourself re-engineering your test setup before testing even begins!
- SO....make sure you have determined the CORRECT STANDARD & LIMITS, designed a VALID TEST SETUP and have ensured you know the location of the BEST RESTAURANTS that Melbourne, Sydney & Auckland have to offer.
SITE RESOURCES TO ASSIST IN DESIGNING YOUR PLAN...
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© Copyright EMC Technologies 1999
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