How to isolate the concentrator's communication ground from its power ground?

The ground and power ground (power supply ground) of the internal communication circuits (RS485, Ethernet) of the concentrator must be isolated to prevent power ground noise from interfering with communication. Magnetic isolation or optical isolation can be used. A communication transceiver chip with isolated power supply (such as ADM2587E) can be used, which achieves complete electrical isolation between the communication ground and power ground through internal transformer coupling. Alternatively, optocouplers can be used to isolate control signals. The primary side (MCU side) of the isolation device uses control power ground (DGND), and the secondary side (interface side) uses isolation ground (ISO_GND). ISO_GND should be connected to the protective ground of the communication port (through a Y capacitor) and maintain a safe distance from the power ground (creepage distance ≥ 8mm). A common-mode inductor CMZ2012A-900T needs to be installed at the output of the DC/DC isolation module powering the isolation side for filtering. Through isolation, the noise voltage between the communication ground and power ground is suppressed to above 1500V, ensuring stable communication.