
Feeder Terminal
REF 541, REF 543, REF 545.
1MRS750443-MBG
13
A050205
Fig. 6
Terminal diagram of the RTD/analog module
Auxiliary voltage
For its operation, the REF 54_ terminal,
including the external display module,
requires a secured auxiliary voltage supply.
The feeder terminal’s internal power supply
module forms the voltages required by the
feeder terminal electronics. The power supply
module is a galvanically isolated (fly-back
type) dc/dc converter. A green protection
LED indicator on the front panel is lit when
the power supply module is in operation.
The feeder terminal is provided with a 48-
hour capacitor back-up protection that
enables the internal clock to keep time in case
of an auxiliary power failure.
Power supply
There are two basic types of power supply
modules available for the REF 54_: type
PS1/_ and type PS2/_. See Tecnical data table
9.The operating range of digital inputs
depends on the type of the power supply
module. See Technical data table 10.