RS-232↔485/422 CONVERTERS
RS-232↔485/422
Converter Plus
Figure 9. Sample Multipoint Operation.
Installation Procedure for the Multipoint Application in Figure 9
1.Set all the RS-232↔485/422 Converters for DCE operation (jumper XW1 in position A).
2.Connect a straight-through cable from the RS-232 port on each RS-232↔485/422 Converter to the RS-232 port on each of the PLCs.
3.Set all the RS-232↔485/422 Converters for normal operation (switch S1 in the “Normal” position).
4.After a remote station has been addressed, two-way data transmission can occur between that station and the industrial controller until the industrial controller sends a “CLEAR” command. This command causes the remote PLC to resume data logging while waiting to be addressed again. Therefore, set each RS-232↔485/422 Converter for full-duplex operation (jumper W8 in the “FULL” [A-B] position).
5.Connect the RS-232↔485/422 Converters together via a 4-wire twisted-pair cable (see Figure 7).
6.Terminate (switch S2 in the TERM position) the two RS-232↔485/422 Converters that have the greatest cable run between them and leave the others unterminated (switch S2 in the UNTERM position).
