10-26
Series 90-30 PLC Installation and Hardware Manual
–
August 2002
GFK-0356Q
10
Shield Treatment
All GE factory made cables are made with a
continuous
, or 100% shield. This means that
the braided cable shield is connected to the metal shell of the connector around the entire perimeter
of the connector. This provides a low impedance path to frame ground for any noise energy that is
coupled onto the cable shield.
For custom length cables made per Figure 10-18, the best noise immunity is achieved when using a
metallized connector cover that makes contact with the cable’s braided and foil shielding and with
the connector shell on the terminating end.
Note
It is
not sufficient
to only solder the drain wire to the connector shell. It is
required that the cable’s shield be continuous across the entire length of the
cable, including at the terminations. The figure below shows the recommended
method for folding the braided shield back before inserting the cable into a
metallized cover.
Split-Ring
Ferrule
Cable
Jacket
Ground Wire
Attach to Pin 1 for custom length cables
Conductors
Foil & Braid
(to be folded back
over ferrule and
ground wire)
OR
Fold back for custom Wye cables. *
*
See “Alert for Users of Early Remote Baseplate Versions" for
description of when to attach drain wire to pin 1.
Figure 10-16. How to use Split-Ring Ferrules for Foil and Braided Cable Shield
For typical industrial applications, all expansion and remote baseplate cables can be made with
plastic shell covers and should be wired as shown in Figure 10-19. In either case, pin 1 should be
wired into both ends of the custom length cable and the recommendations listed below should be
followed for the Wye cables treatment in the remote (IC693CHS392/399) baseplates.
When using 100% shielded cables all local (CPU and expansion) baseplates in the system must be
solidly referenced to the same ground point or a potential difference between baseplates could
disturb signal transmission.
Alert for Users of Early Remote Baseplate Versions
In early remote baseplates versions, IC693CHS393E (and earlier) and IC693CHS399D (and
earlier), it is necessary to remove pin 1 of the mating cable where the cable plugs into the baseplate.
This means that when using a factory made Wye cable, such as IC693CBL300, you must break pin
1 out of the male end where it plugs into the remote baseplate before using it with one of these
baseplates.
Custom built Wye cables for these baseplates should be built using Figure 10-20.