ABB REF 542plus Technical Reference Manual page 13

1MRS755859
Multifunction Protection and Switchbay Control
Unit
Technical Reference Manual
Fig. 3.-3 Mounting of the central unit in the LV compartment and the HMI on the door
REF 542plus is a real-time system. A digital signal processor (DSP) carries out the
measurement and protection functions, and a micro controller (MC) the control
functions. Due to the task separation, there is no impact between the implemented
protection scheme and the control scheme to be modified. An optional
communication processor (CP) is needed when connecting to a station automation
system. A block diagram of the REF 542plus is shown in Fig. 3.-4.
The main module is equipped with the DSP and the MC. The CAN Open interface,
the Ethernet interface for the embedded Web server, the optical input port for time
synchronization are located on the main module as well. The optional
communication module takes care of the communication with the substation
automation system. The binary input and output modules interface the primary
process to send commands and to acquire status information. The analog input
module acquires the current and voltage signals, both from instrument transformers
or non-inductive sensors. The optional analog 0/4 ... 20 mA output module and
analog 4 ... 20 mA input module allow exchanging information with the 4 ... 20 mA
or 0 ... 20 mA current loop.
REF 542plus REF 542plus
A070117
13