Merging Unit; Introduction - ABB REL650 Technical Manual

Section 16
Ethernet
16.4
16.4.1
662
Device 1
AP1
PhyPortA
PhyPortB
PhyPortB PhyPortA
AP1
Device 3
IEC16000038 V1 EN-US
Figure 338: HSR ring

Merging unit

Introduction

The IEC/UCA 61850-9-2LE process bus communication protocol enables an IED
to communicate with devices providing measured values in digital format,
commonly known as Merging Units (MU). The rear access points are used for the
communication.
The merging units (MU) are called so because they can gather analog values from
one or more measuring transformers, sample the data and send the data over
process bus to other clients (or subscribers) in the system. Some merging units are
able to get data from classical measuring transformers, others from non-
conventional measuring transducers and yet others can pick up data from both
types.
Device 2
AP1
PhyPortA PhyPortB
PhyPortB PhyPortA
AP1
Device 4
IEC16000038-1-en.vsdx
Line distance protection REL650 2.2 IEC
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Technical manual