A-10 Series 90-30 PLC Installation and Hardware Manual
–
August 2002 GFK-0356Q
A
RS-422 Point-to-Point Connection
If your host device is equipped with a RS-422 card you can connect directly to Series 90 PLCs as
illustrated in Figure A-6.
TERMINATION RESISTANCE FOR THE RECEIVE DATA (RD) SIGNAL NEEDS TO
CONNECTED ONLY ON UNITS AT THE END OF THE LINES. THIS TERMINATION IS
ON THE SERIES 90 PLC PRODUCTS BY CONNECTING A JUMPER BETWEEN PIN 9
PIN 10 INSIDE THE 15-PIN D-SHELL WITH THE FOLLOWING EXCEPTION. FOR
90-70 PLCs, CATALOG NUMBERS IC697CPU731 AND IC697CPU771, THE
FOR RD AT THE PLC IS IMPLEMENTED BY A JUMPER BETWEEN PIN 9 AND PIN
*
SHIELDED TWISTED PAIRS
PIN PIN
PLC
UP TO A MAXIMUM OF 50 FEET (15.2 METERS)
(WITHOUT ISOLATION)
HOST
COMPUTER
12
13
10
11
9
6
14
8
15
3
2
7
1
SD ( A )
SD ( B )
RD ( A' )
RD ( B ' )
RD
RTS ( A )
RTS ( B )
CTS ( B' )
CTS ( A' )
GND
SHLD
*
RD (A')
RD (B')
SD (A)
SD (B)
CTS (A')
CTS (B')
RTS (B')
RTS (A)
GND
SHLD
Figure A-6. Typical RS-422, Host to PLC Connection, with Handshaking
Multidrop Connections
In the multidrop configuration, the host device is configured as the master and one or more PLCs
are configured as slaves. This method can be used when the maximum distance between the master
and any slave does not exceed 4000 feet (1200 meters). This figure assumes good quality cables
and a
moderately
noisy
environment. A maximum of 8 slaves can be connected using RS-422 in a
daisy chain
or multidrop configuration. The RS-422 line must include handshaking and use wire
type as specified in the “Cable and Connector Specifications” section.
The following illustrations shows wiring diagrams and requirements for connecting a
Workmaster II or IBM-PS/2, Workmaster, IBM-AT/XT or compatible computer to Series 90 PLCs
in an 8-wire multidrop, serial data configuration.
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