Fonrich FR-DCMG-MMPU, Руководство пользователя

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6
RS485 Cable Connection, Shielding, and Grounding
The FG terminal of the FR-DCMG must be grounded, otherwise communication will
interfere and the reliability of the device will decrease. The grounding wire should be
grounded nearby. The grounding wire should be no more than 15cm from the “FG”
terminal to the bottom of the combiner box. It is recommended to be within 10cm. The
shorter the better, the thicker the better. The bottom of the combiner box should be
connected to the ground. The main control unit module is fixed on a standard guide rail
with a width of 3.5 cm.
The wiring specifications of the communication shielded wire are shown in the figure above:
The wiring of on-site communication lines requires that the communication shield can only
be grounded at a single point, otherwise there will be a risk of lightning surge damage to
all equipment on the entire communication line during a lightning strike;
If you encounter a situation where communication line interference is too large to
communicate, you can refer to the figure above, and insert a high voltage capacitor C
<100nF between the shielded wire of each combiner box and the ground wire, and use
this capacitor to filter the shielding layer interference.