How to improve interference immunity?

For challenging applications in harsh conditions, e.g. in industrial environments, disturbances can occur more frequently. Such interference, e.g. powerful motors, usually involves the electromagnetic fields. A device should be as immune as possible to such influences, while also not emitting any interference.

Tests for electromagnetic compatibility (EMC) will help to verify the related product behavior. Moreover, a number of these tests are a part of the product certification measurements.

If the measurements show unwanted influences, the interference immunity must be increased. A distinction is made between these:

• Measures to avoid malfunctions
• Avoidance of propagation from the source
• Avoidance of the effects of the malfunction

Depending on the type of influence detected, countermeasures can be taken, such as the use of capacitors, inductors, protective diodes, better shielding by housing, or a modified mechanical design.

For further information, see the Wikipedia article on electromagnetic compatibility.