Block Diagram - ABB REF 542plus Product Manual

General (cont´d)
4
Feeder Terminal
Fig. 2 REF 542plus installed in an air-insulated switchgear (AIS).
REF 542plus is composed of two parts: a
base unit and a separate human machine
interface (HMI). The base unit contains the
power supply, the processor board, the analog

Block diagram

Analog Output Module
0/4...20mA
Analog Input Module
IL1 IL1
IL2 IL2
IL3 IL3
UL1 UL1
Protection
UL2 UL2
Measurement
UL3 UL3
Io Io
Vo
Main Board
Fig. 3 REF 542plus block diagram.
HMI
The HMI is a stand-alone unit with its own
power supply. It can be installed on the low
voltage (LV) compartment door or in a dedi-
cated compartment close to the base unit.
The HMI can be used to set the protection
parameters to locally operate the switching
devices in the switchgear and to visualize
input board and binary input and output (I/O)
modules, as well as optional modules for sup-
plementary functions. The base unit and a
HMI are connected with a serial cable.
Analog Input Module
0/4...20mA
DSP
start L1
start L2
start L3
Release/Trip
Autoreclosure
CAN Eth.
Binary Input Output Module(s)
events and measurements. A shielded, iso-
lated twisted pair according to the RS-485
standard interface connects the HMI to the
base unit.
Fig. 4 shows an installation of the base unit
and the HMI control unit in the LV compart-
ment.
REF 542plus
1MRS756269
Communication Module
RX RX TX TX
CP CP
Communicatio n P rocessor Communication Processor
µC
Control
Binary Binary
inputs outputs
A050397-c
A070118
A050397