How to ensure EMC (Electronic Compatibility) for long-distance communication with concentrators?

Long-distance communication cables for concentrators (such as kilometer-level RS485) are susceptible to picking up environmental noise and radiating interference. Ensuring EMC requires a comprehensive approach using balanced transmission, shielding, and grounding. Differential balanced transmission (RS485) should be employed, using transceivers with low capacitance and high common-mode rejection ratio. Shielded twisted-pair cables with a small twisted-pair pitch (e.g., <1.5cm) are essential. Shielding grounding strategy: At the concentrator end, the shielding layer is connected to the chassis ground (PE) via a 360° crimp connection; at the remote equipment end, if the equipment is well grounded, the shielding layer is also grounded; otherwise, it floats. If both ends are grounded, a PBZ1608E600Z0T ferrite core can be connected in series in the shielding layer to suppress low-frequency circulating currents. The communication port should be designed with a protective filter circuit as described above. During installation, communication cables should be kept away from high-voltage cables (parallel spacing >30cm), and perpendicular crossings should be avoided if unavoidable. Through these measures, long-distance communication can operate stably in industrial electromagnetic environments with a bit error rate below 10^-7.