How do HMI (Human Machine Delivery) and PLC (Power Management System) communicate and coordinate?

Achieving EMC coordination between HMI and PLC requires system-level consideration to ensure stable operation in a shared electromagnetic environment. First, their communication interfaces should use consistent, interference-resistant protocols and physical layers, such as isolated RS485 or industrial Ethernet. In terms of hardware design, the corresponding interfaces of the HMI and PLC should be configured with similar protection and filtering levels, for example, using the same level of TVS diodes and common-mode chokes. The communication cable connecting the HMI and PLC must be a high-quality shielded twisted-pair cable, with the shield reliably grounded to the respective device's chassis at both ends via shielding clips or connector metal shells, ensuring a 360-degree overlap. If both are installed in the same cabinet, equipotential bonding should be achieved through the cabinet's grounding bus to reduce ground potential difference. During system wiring, communication cables should be kept away from power cables, inverter output cables, and other strong interference sources; if unavoidable, they should cross perpendicularly. The power supplies for the PLC and HMI should ideally come from the same or filtered power source to reduce common-mode interference. In terms of software protocols, mechanisms such as CRC checksums and timeout retransmission should be fully utilized. By implementing system-level planning from interfaces, cables, grounding to wiring, and adopting Eintech's standardized protection and filtering solutions, high reliability of HMI and PLC communication can be achieved in harsh industrial environments.