GE Series 90-30 PLC

I-2 Series 90-30 PLC Installation and Hardware Manual – August 2002 GFK-0356Q
I
Multidrop Cables
There are two sources of multidrop cables:
■ GE Fanuc cable, catalog number IC690CBL714A - This pre-made cable can be purchased
for applications where the PLCs are mounted in the same cabinet, such as in the case of
redundant systems. The length of this cable is 40 inches (1 meter).
■ Custom built - For PLCs that are more than 40 inches (1 meter) apart, it is necessary to build a
custom length cable. The specifications are provide below.
Limitations
■ The maximum cable length between a master (programmer) and slave device (PLC or Option
module) in a multidrop system is 4,000 feet (1,219 meters).
■ The maximum number of slave devices is limited to eight.
Cable and Connector Specifications
The cable assembly presents one of the most common causes of communication failure. For best
performance, construct the cable assemblies using the recommended connector parts and
specifications.
Table I-1. Connector and Cable Specifications
Item Description
Series 90 PLC: Serial (RS-422) port with metric hardware
Connectors Connector: 15-pin male, D-Subminiature Type, Cannon DA15S (solder pot) Hood: AMP
207470-1 connector shell
Hardware Kit: AMP 207871-1 Kit includes 2 metric screws and 2 screw clips
Miniconverter: For connecting to IC690ACC901 miniconverter
Connector: 15-pin female, DB15F,
Hood: AMP #207470-1 or equivalent
M3 Latchblocks: AMP #208101 or equivalent
Computer grade, 24 AWG (.22 mm
2
), minimum with overall shield
Catalog Numbers: Belden 9505, Belden 9306, Belden 9832
Cable These cables provide acceptable operation for data rates up to 19.2 Kbps as follows:
RS-422/RS-422: 4000 feet (1200 meters) maximum length. Must not exceed the
maximum RS-422 Common Mode specification of +7V to –7V.
Isolation at the remote end may be used to reduce or eliminate Common
Mode voltages.
When using RS-422/RS-422, the twisted pairs should be matched so that both transmit signals
make up one twisted pair and both receive signals make up the other twisted pair. If this is
ignored, cross-task resulting from the mismatching will affect the performance of the
communications system.
When routing communication cables outdoors, transient suppression devices can be used to
reduce the possibility of damage due to lightning or static discharge.
Care should be exercised that all connected devices are grounded to a common point.
Failure to do so could result in damage to the equipment.