How to handle the common grounding of multiple loops in an intelligent low-voltage monitoring unit?

Multi-loop grounding employs partitioning and isolation. The system is divided into four zones: power ground, digital ground, analog ground, and communication ground. Each zone is connected at a single point via a PBZ1608E600Z0T ferrite bead or a 0Ω resistor. The PCB design uses a segmented ground plane with a spacing of 1.5mm, and isolation devices such as the ADUM1410 are used for signals crossing zones. The chassis ground is connected to earth ground separately. Through this treatment, ground noise coupling is reduced by 20dB, each loop operates independently, and the conducted immunity test requirements of IEC 61000-4-6 are met.