ABB RER 133 기술 설명 - 페이지 12
{카테고리_이름} ABB RER 133에 대한 기술 설명을 온라인으로 검색하거나 PDF를 다운로드하세요. ABB RER 133 16 페이지. Bus connection module
페이지 인쇄
Bus Connection
Module
12
RER 133
Technical Description
The EIA RS-485 Specification labels the data wires "A" and "B", but many
manufacturers label their wires "+" and "-". In our experience, the "+" wire should
be connected to the "A" line, and the "-" wire to the "B" line.
When wiring RS-485 , use a shielded twisted pair cable with an internal impedance
Ω
of 100-120
. Examples of recommended cables are CAT 5, Belden RS-485 (9841-
9844) and Alpha Wire (Alpha 6222-6230).
The shield of the cables must be directly connected to ground in one
of the nodes. In the other nodes the connection should be made via a
capacitor, i.e. if the shield of the cable is connected to pin 1 in node
1, all the other nodes must be grounded using pin 2.
1
2
3
4
5
6
7
8
Fig. 6.-3 Example on a cable shield connection
1
2
3
4
5
6
7
8
1MRS755163
1
2
3
4
5
6
7
8
A050325