Immunity testing

Competency Group: Electrical Engineering

Type: Compliance Test Hardware 

Description: Immunity tests ensure that a product is immune to common electrical signals and electromagnetic interference (EMI) that will be found in its operating environment, such as electromagnetic radiation or interference from nearby products. An antenna is used to subject the device to electromagnetic waves, covering a large frequency range (usually from 30 MHz to 2.9 GHz). Low frequency signals (usually 10 kHz to 80 MHz) are injected onto the data and power lines of a device. This test is used to simulate the coupling of low frequency signals onto the power and data lines. Bursts of high voltage pulses are applied to the power lines to simulate events such as repeating voltage spikes from a motor. Electrostatic discharges with various properties (rise time, peak voltage, fall time, and half time) are applied to the areas on the device that are likely to be discharged too, such as the faces, near user accessible buttons, etc. Discharges are also applied to a vertical and horizontal ground plane to simulate an ESD event on a nearby surface. Voltages are usually from 2kV to 15kV, but commonly go as high as 25kV or more. Standard laboratory equipment required — specialized equipment may be used at times.

Citation for Description: Conformance testing. (2011). Retrieved from Wikipedia, http://en.wikipedia.org/w/index.php?title=Conformance_testing&oldid=467938354

Units: Pass/Fail

Advantages: Can provide valuable information on how the device may interact with other devices.

Limitations: Can be expensive to test these devices in electrically and magnetically shielded rooms.

Regulations: Magnon, D., Feybesse, A., & Guitton, F. (1999). Burst immunity tests according to IEC 1000-4-4 standard used to improve design of a new integrated power function. 1999 IEEE International Symposium on Electromagnetic Compatibility, 1, 351-354. doi: 10.1109/ISEMC.1999.812926 

Target Audience: Engineering

Relevant to Universal Design: Yes

Stages and Steps: 5, 6

Free Resource: Elliot. (2012). Immunity. Retrieved from http://www.elliottlabs.com/services_emc_immunity.htm

Purchase Resource: Laughton, M.A., & Warne, D.F. (2003). Electrical Engineers Reference Book. Burlington, MA: Elsevier Science.