What are the EMC differences between HMI field and laboratory settings?

The EMC performance of HMI products in field applications may differ from that in standard laboratory tests. Understanding these differences is crucial for ensuring reliable product operation. The differences primarily stem from:

1. Different electromagnetic background noise levels in the testing environment: Laboratory environments are pristine, while field environments may contain various unknown sources of strong interference, such as frequency converters and wireless equipment.

2. Different interference application methods: Laboratory tests involve single, standardized interference, while field interference is often complex, random, and multi-point.

3. Different equipment installation and grounding conditions: Laboratories have standard grounding reference boards, while field grounding conditions may be suboptimal, with high ground impedance or ground loops.

4. Different cable routing: Laboratory tests follow standard cable routing, while field cables may run parallel to power lines for extended distances, leading to enhanced coupling.

5. Different equipment operating states: Laboratory tests are typically conducted in specific modes, while field equipment operates under full-function, complex conditions.

Therefore, even products that have passed laboratory certification may experience problems in the field. Countermeasures include: incorporating sufficient margins in the design; designing based on worst-case field environment assumptions; enhancing port protection and filtering levels; and providing clear field installation guidelines, emphasizing grounding and cabling specifications. Etymotic's high-level protection devices and filtering solutions can help HMI products better adapt to harsh field electromagnetic environments.