Rockwell Automation T8xxx Trusted Communications Interface - Manual (Page 55)

Trusted
TM
Communication Interface T8151B
Issue 21 Apr 10 PD-T8151B 55
6.2.6. Maximum Cable Length
The maximum length of an RS485 system is dependant on cable type, data rate and termination. For
example, the EIA RS-422-A standard gives a maximum length of 4000ft (approx. 1.2Km) for 24AWG
twisted pair telephone cable that has a shunt capacitance of 16pF/ft, a 100R termination and a data
rate of 100Kbits/s.
6.2.7. RS485 Connections
The pin outs and signal labels for the Communication Interface RS485 ports are shown in Table 21
below. Further details are given in PD-8153.
CI DIN41612
Plug (PL5) Interface Adapter
5 Way Phoenix
Contact Socket Standard EIA
Circuit designation Note:
Labels are shown the same as
those on the Product Descriptions.
RX/TX = Receive circuit in 4 wire
applications. Multiplexed circuit for
2 wire applications.
GND = Signal Ground.
There are actually 2 identical
connectors on the Interface Adapter
for each port. This is to allow either
side of multi-drop connections to be
connected to separate connectors.
No ‘To’ connections have been
shown as there is no standard
connector for RS485 and many
devices have terminal blocks for the
connections.
J4 & J5
C9 (GND1) 1 (GND) GND
A9 (BO1) 2 (TXB) TXB
B9 (AO1) 3 (TXA) TXA
A8 (BIO1) 4 (RX/TXB) RXB
B8 (AIO1) 5 (RX/TXA) RXA
J9 & J10
C13 (GND2) 1 (GND) GND
A13(BO2) 2 (TXB) TXB
B13 (AO2) 3 (TXA) TXA
A12 (BIO2) 4 (RX/TXB) RXB
B12 (AIO2) 5 (RX/TXA) RXA
J11 & J12
C15 (GND3) 1 (GND) GND
C16 (GND3) 1 (GND) GND
A16 (BO3) 2 (TXB) TXB
B16 (AO3) 3 (TXA) TXA
A15 (BIO3) 4 (RX/TXB) RXB
B15 (AIO3) 5 (RX/TXA) RXA
J13 & J14
C18 (GND4) 1 (GND) GND
C19 (GND4) 1 (GND) GND
A19 (BO4) 2 (TXB) TXB
B19 (AO4) 3 (TXA) TXA
A18 (BIO4) 4 (RX/TXB) RXB
B18 (AIO4) 5 (RX/TXA) RXA
Table 21 CI Cable Wiring for RS485