IC655CCM590 Converter
GFK-0356Q Appendix C IC655CCM690 Isolated Repeater/Converter C-5
C
RD ( A' )
RD ( B' )
SD ( A )
SD ( B )
CTS ( A' )
CTS ( B' )
RTS ( A )
RTS ( B )
RS-422
TWISTED SHIELDED
PAIRS
RS-232
SHIELDED
PAIRS
*
2
3
12
13
10
11
9
6
14
15
8
7
1
SD ( A )
SD ( B )
RD ( A' )
RD ( B' )
RT
RTS ( A )
RTS ( B )
CTS ( A' )
CTS ( B' )
0V
SHLD
a44783
PIN
SERIES
90 PLC
RS-422
PORT
25-PIN
FEMALE
RS-422
PORT
RS-422 ISOLATED REPEATER
RS-232 CONVERTER
(IC655CCM590)
25-PIN
FEMALE
RS-232/
RS-422
PORT
RD
SD
CTS
RTS
GND
3
2
5
4
7
PIN
25-PIN
MALE
PIN
15
14
16
17
11
10
13
12
7
25- PIN
MALE
PIN
TD
RD
RTS
CTS
DCD
DTR
GND
HOST
COMPUTER
*
15- PIN
MALE
15- PIN
FEMALE
J1J2
115VAC
TERMINATION RESISTANCE FOR THE RECEIVE DATA (RD) SIGNAL NEEDS TO BE CONNECTED ONLY ON UNITS AT THE END OF THE LINES.
THIS TERMINATION IS MADE ON THE SERIES 90 PLC PRODUCTS BY CONNECTING A JUMPER BETWEEN PIN 9 AND PIN 10 INSIDE THE
15-PIN D-SHELL WITH THE FOLLOWING EXCEPTION. FOR SERIES 90-70 PLCs, CATALOG NUMBERS IC697CPU731 AND IC697CPU771,
THE TERMINATION FOR RD AT THE PLC IS IMPLEMENTED BY A JUMPER BETWEEN PIN 9 AND PIN 11.
0V
22
23
**
RD (A')
RD (B')
** SWITCH IN CENTER POSITION
150
Ω
Figure C-3. Example RS-422 Isolated Repeater/RS-232 Converter Connection
System Configurations
The figures below show various ways you can connect the Isolated Repeater/Converter to convert
signals, expand the number of drops, and obtain greater distance. Any system configuration can be
reduced to a minimum number of cables each covering a part of the overall system configuration.
The following examples of system configurations refer to these cables as Cables A through E
which are described in
Cable Diagrams
later in this section.
Downstream and Upstream Contention. In this section, simple multidrop configurations are
those where a single Isolated Repeater/Converter is used. Complex multidrop configurations
contain one or more multidrop sections where an Isolated Repeater/Converter is included as one
of the drops. In both simple and complex multidrop configurations, the transmitters directed
downstream from the master can be on at all times. There will be no contention for the
communication line because only one device (the master) transmits downstream.
In simple multidrop configurations, there will be no contention when transmitting upstream as long
as devices tri-state their drivers when idle and turn them on only when they have something to
transmit. This is the case for the Series 90-70 and Series 90-30 CMMs.
In complex multidrop configurations, however, special steps must be taken to switch the upstream
transmitters of the Isolated Repeater/Converter.
Switching Upstream Transmitters. For the RS-422 drivers to be active at the J2 port of the
Isolated Repeater/Converter, the RTS input at J1 must be true. The state of the RS-422 drivers at
the J1 port depends on the position of the switch on the unit. When the switch is in the center
position, the J1 transmitters will always be turned on. When the switch is in the CTS position,
(toward the power cable), then either the RS-232 or RS-422 CTS signal must be true to turn on the
J1 drivers.
Note: Note the position of the switch on the Isolated/Repeater Converter in the system
configurations below.
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