How can the PMS metering circuit for electrical force measurement be kept away from interference sources?

The metering circuitry (ADC, reference, signal conditioning) of a PMS is extremely sensitive to noise and must be placed away from various interference sources. Interference sources include: transformers and MOSFETs in switching power supplies, relay/contactor coils, clock areas of digital chips, communication interfaces, and power input terminals. During PCB layout, the metering circuitry should be centrally located in a quiet corner of the board, maintaining a distance of at least 30mm from the aforementioned interference sources. If space is limited, a grounded shield or metal partition can be installed between the metering area and the interference sources.

Simultaneously, the power supply for the metering circuitry should be independently obtained from the input front end of the power module and pass through LC filtering (such as PBZ1608E600Z0T and capacitors) and LDO regulation, avoiding sharing power traces with digital circuits. Signal traces should avoid crossing above or below interference sources. Structurally, the metering circuitry can be fabricated as an independent daughterboard, connected to the main board via connectors to achieve physical isolation. By keeping it away from interference sources and combining shielding and filtering, the noise level of the metering circuitry environment can be reduced by 30dB, bringing the effective number of bits (ENOB) of the ADC close to the theoretical value and ensuring high-precision metering.