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SERIAL INTERFACE (OPTION)
12 - 5
ETC00781(1) Series 100 e 10/2001
Rosemount Analytical
12.3.2 RS 485
Configure 2- or 4-wire operation via solder bridge LB 1 of PCB SIF 485 before mounting the PCB.
Connecting of [1 - 2] 2-wire-operation is selected. Connecting of [2 - 3] 4-wire-operation is active.
Switch on network termination via soldering bridges at both ends of interface connection. For
network operation with several analyzers via RS485 interface, termination has to be done at both
ends of network connection only. For the other analyzers the soldering bridges have to be open.
Close soldering bridge LB2 for 2-wire-operation. For 4-wire-operation close LB2 and LB3.
Fig. 12-3: Pin Assignments “RS 485 Interface”
In contrast to RS 232 C operation, simultaneous transmission and reception is not implemented
in this standard. This would not result in damage to the electronics, but could lead to destroy of
data. The analyzer behaves passively in this mode of operation; i.e., it keeps its transceiver set for
reception whenever it is not transmitting. Since the time periods for transmission and reception are
controlled by protocols, “data collisions” are excluded.
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1 GND
2 RxD-
3 RxD+
4 TxD+
5 TxD-
6 not used
7 not used
8 not used
9 not used
6
9
1
5
6
9
15