Check List - Immunity Test
Note: Elliott may cut your shielded cables to perform conducted immunity tests. Please contact your Project Manager in advance of any immunity testing to discuss the use of shielded cables.
During immunity testing, if you intend to remotely locate your support equipment from the EUT, please bring at least 25' (7.6 meter) cables.
During immunity testing, your EUT should be exercised so any degradation in performance may easily be observed. For example, this might include the visual monitoring of displays or LEDs or the use of audio analyzers or bit error rate testers. You should carefully consider what would constitute a failure for a particular test and how this would be monitored. Please refer to the "Examples of Immunity Criteria (A, B, C)" section for a description of common immunity tests and performance criteria.
The following are generic examples of immunity test criteria found in some European product and generic immunity standards. These criteria are only examples of performance objectives for a specific test; specific criteria must be established for each product.
Different performance criteria are allowed for different immunity tests. The interpretation of each criterion is based upon what the user should expect from the product during typical operation.
Criterion A - Your EUT continues to operate as intended. No degradation of performance is allowed below the performance level specified by the manufacturer. Any degradation in performance should be transparent to the end-user. When testing Information Technology Equipment (ITE) Local Area Networks (LANs), it's necessary to monitor the error rate, transmissions rate, loss of link, and requests for retry.
Criterion B - Your EUT continues to operate as intended after the test with no performance degradation below the level specified by the manufacturer. During the test, some loss of performance is allowed but no loss of data or change in operating state is allowed. The end-user may notice the EUT has not performed correctly but should not have to do anything to cause it to resume its correct performance. There may be some exceptions (e.g., certain lab equipment should inform the user that an error has occurred requiring a repeat measurement).
Criterion C - Temporary loss of function is allowed provided normal functioning is recoverable. The end-user may notice a system failure has occurred but should be able to restore the EUT to its correct operating conditions and performance level even if it requires power cycling or a reboot sequence.
When performing immunity tests, it's important the performance criteria and monitoring method are clearly defined. Your product should be fully exercised and all failures should be easily observed. This may require the use of special software, with a halt-on-error routine for the tests that require Criterion A and a continue-on-error routine for Criterion B. This will give our test engineer a clear indication whether or not the EUT has met the required performance level. It's preferable to have an objective set of metrics (such as Bit Error Rate, SINAD, etc.), rather than a subjective metric (such as watching for the LED to stop flashing, or watching a monitor for distortion). Also, you can monitor your system's performance with our video cameras and audio amplifiers.
