GE 90-30 PLC Series Installation And Hardware Manual page 373

C
IC655CCM590 Converter
Rules for Using Repeater/Converters in Complex Networks
When designing a complex multidrop network including PLCs and RS-422 repeater/converters
(bricks), the following rules apply:
Rule 1: When using a brick as a repeater, port J2 should always be directed toward the host
device, and Port J should always be directed away from the host device. The switch located on
the side of the brick should always be in the center position (ON). The only case in which Port J
is directed toward the host is when the brick is used as a converter (RS-232) at the slave. The
switch is in the right position (CTS).
Rule 2: If a Series 90 CMM slave device is located downstream of a brick, set the configuration of
the CMM serial port to NONE flow control with a 0 ms Modem Turnaround Delay (Applies to
CCM, SNP, and SNP-X protocols only).
Rule 3: Do not place more than three bricks in a single communication path between the host and
the slave devices.
GFK-0356Q Appendix C IC655CCM690 Isolated Repeater/Converter C-7