Rs485 Bus Termination - BONFIGLIOLI Vectron Agile Communications Manual

5.2.2.3 RS485 Communication Module CM-485T
Terminal Name
1 Data Line A
2 Data Line A'
3 Data Line B
4 Date Line B'
5 +5 V
6 0 V
7 PE
5.2.3

RS485 Bus Termination

Attention!
The passive bus termination (connection of a termination resistor), is required at the physically first
and last client. It can be activated by the CM-485 and CM-485T DIP Switch S1.
By default, the bus termination is set to OFF.
It is important to implement a correct termination. Otherwise, no communication is possible via the
RS485-Interface.
As an alternative, the active bus termination is possible via a corresponding circuit:
The active termination is only allowed once on each branch. The bus termination via an external cir-
cuit and via DIP switch at the same time is not allowed.
Pay attention to the ground wiring. This will protect the communication bus against high noise level.
For easy wiring the signal terminals A and B have parallel contacts.
02/2011
The RS485-Interface is connected via the 7-pin terminal
socket X310.
For details on the pin assignment, refer to the following
table.
Bus Connector X310 CM-485 T (7-pin terminal socket)
Function
short-circuit proof and functionally insulated; max. current 60 mA
same as pin 1 – for cable network
short-circuit proof and functionally insulated; max. current 60 mA
same as pin 3 – for cable network
Interface converter supply voltage +5 V
GND/earth
Shield
Pin 7
Data line A
Pin 8
Pin 1
Data line B
Pin 2
Modbus Agile
Pin 5 +5 V
330 Ω
22.1 Ω
150 Ω
22.1 Ω
330 Ω
Pin 3 0 V
GND
17