3 System Installation
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3.6 Electrical connections
3.6.1 Cable requirements
The choice of cable should comply with relevant national standards and meet the load requirements.
Power cable requirements
Refer to the electrical data in the product data, and then consider the ambient temperature, current,
margin and other factors to select the cable specifications.
Communication cable requirements
Because weak communication signals are susceptible to external interference, the communication
cable requires a shielded cable and grounds its shield as shown in the following figure. Also refer to the
relevant document "GB 50217-2007 Cable Design Specification".
(a) Double shielded twisted pair
When the cable is insulated by two layers, the outermost shield is
grounded at both ends, and the inner shield is equipotentially
grounded.
(b) Multiple pairs of twisted pairs of single
shield
When the cable is insulated and shielded by a single screen, in
order to prevent the potential difference from being formed, the
shield can be equipotentially grounded at one end.
Figure 3-7 Twisted pair with shield
The RS485 communication cable generally has four thin wires (blue, brown, gray, and black,
respectively) and one shielded grounded copper wire. When wiring, cut off the gray line, use the blue
line, brown line and black line, as shown below, and wrap the shield grounding copper wire on the black
line (need to ensure that the copper wire is longer than the black line, To prevent the copper wire from
being pulled off, connect the RS485 PE terminal.
Figure 3-8 RS485 communication cable schematic
