Immunity standards

Immunity tests are designed to ensure that the product will work as specified in a typical environment. Industrial environments are considered to be more stressful than domestic or commercial, and this is reflected in the stress levels that are applied.  

 During any test, the operation of the product must be monitored and any degradation in performance noted. For some products, some degradation may be deemed acceptable, provided that this is written into the user documentation, is not permanent and does not with safety or operational requirements.

There are 3 performance criteria...

 Level A:   No degradation in performance or specification. Essential for safety critical equipment.

Level B:   Some degradation in performance and some loss of functionallity, but product completely recovers automatically once the stress is removed. No safety or mission critical consequences.

Level C:   Some degradation in performance and some loss of functionallity, but product requires manual intervention in order to resume operation once the stress is removed. No safety or mission critical consequences.

There are several types of immunity tests, each covered by an IEC standard.

 Standard

 Type

 Laplace Supply?

 IEC61000-4-2

 ESD
(electostatic Discharge)

Yes

 IEC61000-4-3

 RF radiated interference

 Yes

 IEC61000-4-4

Electrical fast transient/burst

Yes*

 IEC61000-4-5

Surge

 Yes*

 IEC61000-4-6

 RF Conducted interference

 Yes

 IEC61000-4-8

 Power frequency magnetic field

 Yes*

 IEC61000-4-9 Pulsed magnetic field Yes*

 IEC61000-4-11

Voltage dips, interruptions & variations (ac)

 Yes*

 IEC61000-4-29

 Voltage dips, interruptions & variations (dc)

 Yes*

Most generic and product specific standards list most of the above as required for compliance testing. However, the DTI (Department for Trade and Industry in the UK) has advised that judgement should be used in deciding what tests are actually performed. For many non-critical products, some temporary failure due to an immunity problem may be a reliability issue, rather than a compliance issue, so these issues tend to be self regulating with manufacturers striving to improve the product due to customer pressure and thier own reputation.

Some 'informal' tests are relatively easy to perform at low cost.

BUT, if the product is in any way a safety critical item... then full testing is absolutely essential.

Laplace is able to supply comprehensive and complete test systems for the two RF tests, radiated and conducted RF, (IEC61000-4-3 and IEC61000-4-6).
We also offer the ONYX16 ESD simulator for IEC61000-4-2 and the AXOS5 test system (with relevant options) for the items marked *. This integrated system covers all the marked tests with one unit.