GE 90-30 PLC Series Installation And Hardware Manual page 354

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.
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 ( 200 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.
A-10 Series 90-30 PLC Installation and Hardware Manual – August 2002
HOST
COMPUTER
PIN
RD (A')
RD (B')
SD (A)
SD (B)
CTS (A')
CTS (B')
RTS (B')
RTS (A)
GND
SHLD
UP TO A MAXIMUM OF 50 FEET (15.2 METERS)
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
O
FOR RD AT THE PLC IS IMPLEMENTED BY A JUMPER BETWEEN PIN 9 AND PIN
SHIELDED TWISTED PAIRS
(WITHOUT ISOLATION)
PLC
PIN
12 SD ( A )
13
SD ( B )
10 RD ( A' )
11 RD ( B ' )
9 RD
* 6 RTS ( A )
14 RTS ( B )
8
CTS ( B' )
15 CTS ( A' )
3 GND
2 SHLD
7
1
GFK-0356Q