ABB Industrial IT enabled REX 521 Technical Reference Manual, General page 29

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Technical Reference Manual, General
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SPA bus, glass fibre optics
Maximum length with plastic fibre: 20 m
Maximum length with glass fibre: 1000 m
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The protection relay is able to interface to the substation automation system with the
LON communication protocol. The LON communication between REX 521 and the
host device, for example MicroSCADA, is based on LAG (Lon Application
Guideline) version 1.4. The REX 521 LON communication includes vertical
communication of process data and parameter data between the protection relay and
the host device.
The system very often resembles the system in the figure below. The protection,
control or alarm functions are implemented by using REX 521 protection relays and
other RED 500 series protection relays, SPACOM units or other SPA bus devices
(devices connected to the system via the SPA bus). LON devices made by other
manufacturers or other ABB companies may be used for various DI, AI and DO
functions. MicroSCADA is used for remote control.
MicroSCADA
SPA-ZC22
SPA bus (loop), plastic fibre optics
R E X 5 2x R E X 5 2x
REX 521
REX 521
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REX 521
REX 521
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