16
1MRS750881-MUM
Remote Monitoring and Control Unit
Technical Reference Manual
REC 523
The REC 523 unit measures, for example, phase currents, neutral currents, phase-to-
phase or phase-to-earth voltages and residual voltages. The power factor, active and
reactive power are calculated from measured currents and voltages. Energy can be
calculated on the basis of the measured power. The measured values can be
indicated remotely as scaled primary values.
In addition to measurement and control functions, the REC 523 units are provided
with a large amount of programmable logic controller (PLC) functions allowing all
the functions needed for secondary substation automation to be integrated into one
unit. The data communication properties include communication over:
• SPA bus
• LON bus
• Modbus (RTU and ASCII)
• IEC 60870-5-101
• DNP 3.0 with higher-level equipment.
The flexibility of REC 523 makes it possible to use a wide range of communication
methods such as switched line telephone, leased line, optical cable, digital and
analogue mobile networks, radio modems, packet radio networks, radio links and
TETRA network.
Fig. 4.1.-2 Application example of the REC 523 unit
REC 523
+12V
Radio
+24V
O
C
MV
1
2
9
1
2
15
1
2
9
IRF
M
Heating
RS232
Open
Close
Enclosure UEMC A2
Remote
off
on
aux
523SEC_b
