Will edge boxes exhibit data anomalies under strong magnetic fields?

The data anomalies of the edge computing box under a strong magnetic field of 100A/m power frequency are mainly caused by differential-mode voltage induced by magnetic flux in the signal loop. For example, the RS485 communication level is only 200mV, and the induced voltage can reach 50mV in a loop area of 10cm², leading to logical misjudgments. To eliminate the anomalies, the following measures are taken:

1. Connect all exposed interface signal lines to ground in parallel with a TVS array ESDSM712. SM712 is named as having dual shutdown voltages of 7V and 12V, adapting to RS485 and clamping induced surges.

2. Use shielded twisted-pair cables with single-end grounding; the shielding layer cuts off magnetic field coupling.

3. Control the differential line spacing to within 5mil and keep it close to the reference plane to reduce the loop area.

4. Connect a common-mode inductor CML3225A-510T in series at the interface. CML common-mode inductor 3225, size 3.2×2.5mm. The 510T inductor with a capacity of 51μH exhibits high resistance to the induced current in a common-mode magnetic field. Verified by the EMC laboratory of Yinte Electronics, the bit error rate of edge box communication was reduced from 10^-4 to below 10^-9 when a 100A/m power frequency magnetic field was applied, and there was no packet loss during data acquisition.