How can the monitoring circuit of an intelligent low-voltage monitoring unit be kept away from interference sources?

The monitoring circuit is spatially isolated and electrically shielded from interference sources. Spatially, the monitoring circuit is more than 100mm away from the switching power supply and more than 80mm away from the motor drive circuit. Electrically, the monitoring circuit is powered by an independent power supply module WRB2405S-3W. Shielded twisted-pair cables are used for the signal lines. A shielding cover is installed in the monitoring circuit area on the PCB. The monitoring input signal is protected by RC filtering (1kΩ + 100nF) and ESD5V0D8B protection. Through this design, the coupling of interference sources to the monitoring circuit is reduced by 35dB, and the measurement error is less than 0.2%.