Feeder Terminal
REF 541, REF 543, REF 545.
1MRS750443-MBG
7
determine the oscillation level and hysteresis
for all digital inputs. Event is generated in
case oscillation is detected.
Attributes of a digital input for feeder ter-
minal configuration
For each digital input, the status of the input
(value), the time tag for the status change
(time) and the validity of the digital input
(invalidity) can be issued by the attributes.
These attributes are available in the feeder
terminal configuration and can be used for
various purposes.
RTD/analogue inputs
The REF 541 and REF 543 feeder terminals
equipped with an RTD/analogue module
(RTD1) have eight general purpose analogue
inputs for DC measurement. The RTD/ana-
logue inputs are galvanically isolated from
the feeder terminal power supply and enclo-
sure. However, the inputs have a common
ground. The general purpose RTD/analogue
inputs accept voltage-, current- or resistance-
type signals. For each measuring mode, a
separate parameter is provided for choosing
between the available measurement ranges.
RTD/analogue inputs can be applied for e.g.
temperature measurement.
Digital outputs
The outputs of the feeder terminal are catego-
rized as follows:
• HSPO: High-speed power output, double-
pole contact, preferred for tripping pur-
poses and for circuit breaker and discon-
nector control
• PO: Power output, either single-pole or
double-pole contact, preferred for circuit
breaker and disconnector control
• SO: Signal output, either NO (Normally
Open) or NO/NC (Normally Open/Nor-
mally Closed) contact. The output contact
is a normal-duty contact and cannot be
used for controlling a heavy load such as a
circuit breaker.
Analogue outputs
The REF 541 and REF 543 feeder terminals
equipped with an RTD/analogue module have
four general purpose 0...20 mA analogue cur-
rent outputs. All outputs are galvanically iso-
lated from the supply and enclosure of the
feeder terminal and from each other.
Analogue outputs can be utilized for transfer-
ring any measured or calculated information
to panel meters or e.g. PLCs.
Alarm LED indicators
The feeder terminal offers eight alarm LED
indicators to be configured with the Relay
Mimic Editor. The LED colours (green, yel-
low, red), their use, and the ON and OFF state
texts can be freely defined. Three basic oper-
ation modes are supported: non-latched,
latched-steady and latched flashflashing.
Alarms can be acknowledged remotely,
locally or by using logic of the feeder termi-
nal.
The alarm channels include time tagging for
detected alarms. The time tagging principle
used depends on the operation mode.
Interlocking LED indicator
The interlocking LED indicates that control
operation has been interlocked or that the
interlocking is in bybass mode, e.g. when
control is possible despite of interlocking.
Trip Circuit Supervision
The purpose of this function is to supervise
the tripping circuitry of the circuit breaker.
An alarm will be generated in case a faulty
tripping circuit, e.g. a circuit is not able to
perform a trip, is detected.
The supervision is based on the constant-cur-
rent injection through the tripping circuitry.
Display panel
The feeder terminal is provided with either a
fixed display or an external display module.
The external display module requires a sepa-
rate voltage supply from a common source
with the main unit. The display consists of 19
rows divided into two windows: a main win-
dow (17 rows) and an assisting window
(2 rows).
The graphic display presents detailed infor-
mation on MIMIC, objects, events, measure-
ments, control alarms, and parameters. The
assisting window is used for terminal-depen-
dent indications/alarms and help messages.
Additionally, the panel includes the following
HMI items:
• three push-buttons for object control (I, O,
object selection)
• eight freely programmable alarm LEDs
with different colours and modes accord-
ing to the configuration
• LED indicator for control interlocking
• three protection LED indicators
• HMI push-button section with four arrow
buttons and buttons for clear and enter
