USER MANUAL 1.2 | B-FORTIS CC-PRIME SERIES
Berghof Automation GmbH | Arbachtalstrasse 26 | 72800 Eningen |
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5.3.7. RS 485 / RS 232 interface
Fig. 18: RS 485 / RS 232 interface
Assignment RS 485 / RS 232 interface plug X8
Pin
Assignment
Pin
Assignment
1
RS 232 RX
5
RS 485 Tx/Rx
–
2
RS 232 TX
6
NC
3
NC
7
ECC22X2: 5 V
Other variants: reserved
4
RS 485 Tx/Rx+
8
ISO GND
If the RS-485 interface is located at the start or end of the bus topology:
set switch S3 to ON in order to switch on the 120 Ω terminal resistance between Tx/Rx+ and
Tx/Rx
–.
As far as possible, the assignment of the interfaces should be carried out in accordance
with the specifications given in “MODBUS over Serial Line; Specification and
Implementation Guide V1.02”.
Fig. 19: RS 485 switchable terminating resistor