MIL-STD-461F is an important military testing standard because it ensures that the ruggedized computer systems purchased from vendors can function properly within electromagnetic (EM) environments and avoid releasing EM energy that could potentially cause EM interference (EMI) with nearby devices.
The MIL-STD-461F document is applied to electrical or electronic systems, e.g., rugged servers and workstations, used in military programs and applications. A MIL-STD-461 certification ensures that a system doesn’t suffer from EM interference or disrupt other devices near it.
MIL-STD-461F establishes interface and associated verification requirements for the control of the electromagnetic interference (EMI) emission and susceptibility characteristics of electronic, electrical, and electromechanical equipment and subsystems designed or procured for use by activities and agencies of the DoD.
This standard is best suited for items that have the following features:
- Electronic enclosures that are no larger than an equipment rack
- Electrical interconnections that are discrete wiring harnesses between enclosures
- Electrical power input derived from prime power sources
MIL-STD-461 contains about 20 test parameters, of which 10-12 are relevant for the majority of the products. The standard is very systematic, with set terms for the different test parameters.
All emission test parameters have E as the last letter. For example: RE – Radiated Emission for all radiated emission tests. Likewise, immunity parameters are referred to with an S for Susceptibility, which is the standard’s term for vulnerability. Susceptibility is the inverse expression for immunity. For example: Conducted Susceptibility for conducted immunity tests. In addition, the tests have 3-digit serial numbers.
In connection with the publication of version G, the scope of the test has been slightly expanded, so that for example the ESD test CS118 (test with electrostatic discharges) which corresponds completely to the civilian ESD standard IEC 61000-4-2, has been added.
In line with the system used in the MIL standard, one special feature has been added however: A mandatory “check” of the test setting before you carry out the test on your product. You must verify that there is actually voltage present at the outlet of the ESD simulator before testing, just as you must verify for all the other tests that the test signal is correctly adjusted before completing a test.
All emission measurements must contain a set of data, where a known signal is applied to a measuring network, current probe or antenna to verify that it measures as expected. This is built-in quality assurance and thus good laboratory practice.
Want to learn more? Tonex offers MIL STD 461F Training, a 3-day course that provides the information and skills required to implement MIL-STD-461F, the standard that regulates boundary and relevant verification criteria for the regulation of the electromagnetic interference (EMI) emission and vulnerability features of electronic, electrical, and electromechanical instruments and subsystems planned or acquired for application by actions and organizations of the Department of Defense (DoD).
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