How should the spacing between the power line and signal line of the power measurement switch (PMS) be set?

Improper spacing between power lines (carrying high current, high di/dt) and signal lines (especially low-level analog signals) within a power supply system (PSS) can cause severe interference through magnetic and electric field coupling. Spacing settings must comprehensively consider voltage difference, current change rate, and signal sensitivity. A rule of thumb: For low-voltage, small signals (such as ADC inputs), the parallel spacing between the power line and the signal line should be at least 10 times the line width and not less than 2mm. For 400VAC main circuits, the spacing should be greater than 10mm. If the power line current change rate is large (such as the chopper circuit of a switching power supply), the spacing needs to be further increased, or it can be changed to a perpendicular crossover. In multilayer PCBs, an intermediate ground plane can be used to isolate power lines and signal lines on different layers. When the spacing cannot meet the requirements, a grounded guard trace or a grounded copper shield must be inserted between them. All spacing rules should be pre-defined in the PCB design rules and enforced. By properly setting the spacing, the coupling capacitance between power lines and signal lines can be reduced by an order of magnitude, and the induced noise voltage can be reduced by more than 20dB, ensuring signal integrity.