P&B MR-REF User manual

MR-REF & MR-REF3 Technical Manual
Issue 3, November 2013

MR
-
REF & MR
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REF3
Technical Manual
Issue 3, November 2013
Contents
1. P&B MR-REF & MR-REF3 .................................................................................................................................................................................1
1.1 Principle of operation...................................................................................................................................................................................2
Unbiased Differential....................................................................................................................................................................2
Restricted Earth Fault Protection for Transformers.......................................................................................................................3
1.3 Displayed Feeder Data................................................................................................................................................................................4
1.4 Control Functions. .......................................................................................................................................................................................4
2. Technical Specification. ......................................................................................................................................................................................5
3. Environmental Tests...........................................................................................................................................................................................6
4. Inputs and Outputs. ............................................................................................................................................................................................7
4.1. Power Supply Live......................................................................................................................................................................................7
4.3. Current Transformer Inputs. .......................................................................................................................................................................7
4.4. Output Relays.............................................................................................................................................................................................7
4.5. Digital Inputs. .............................................................................................................................................................................................7
4.6. RS485 Rear Port. .......................................................................................................................................................................................7
4.7. RS232/USB Front Port. ..............................................................................................................................................................................7
5. Faceplate Functions. ..........................................................................................................................................................................................8
5.1 LED Status ..................................................................................................................................................................................................8
6. LCD Display. ......................................................................................................................................................................................................9
6.1. Menu Screens. ...........................................................................................................................................................................................9
6.2. Display Scroll............................................................................................................................................................................................10
6.3. Feeder Settings........................................................................................................................................................................................11
E/F CT Primary. .........................................................................................................................................................................11
6.4. Serial Settings. .........................................................................................................................................................................................12
6.5. I/O Settings (Input / Output Settings). .......................................................................................................................................................14
6.5.1 Digital Inputs .....................................................................................................................................................................................14
Reset Fault.................................................................................................................................................................................14
Block..........................................................................................................................................................................................14
6.5.2 Relay Outputs ...................................................................................................................................................................................15
Trip.............................................................................................................................................................................................15
Trip Fail Safe.............................................................................................................................................................................. 15
Alarm. ........................................................................................................................................................................................15
Alarm Fail Safe...........................................................................................................................................................................15
Healthy.......................................................................................................................................................................................15
Healthy Fail Safe........................................................................................................................................................................15
Internal Fail. “Intrnl Fail” .............................................................................................................................................................15
Serial Timeout. "Ser Timeout" ....................................................................................................................................................15
6.6. System Settings. .................................................................................................................................................................16
Password. ..................................................................................................................................................................................16
Engineering Password ...............................................................................................................................................................16
Change Password......................................................................................................................................................................16
Contrast and LCD Backlight. ......................................................................................................................................................16
Set Default Page / Default Return Time......................................................................................................................................16
Time Sync Delay. .......................................................................................................................................................................16
Software Version........................................................................................................................................................................ 16
Serial Number. ...........................................................................................................................................................................16
Disturbance Recording Activation Key........................................................................................................................................17
Time and Date............................................................................................................................................................................17
Chronovision ..............................................................................................................................................................................17
Screen Saver and Screen Saver Time .......................................................................................................................................17
6.7. Protect Settings........................................................................................................................................................................................18
Function. ....................................................................................................................................................................................19
Alarm. ........................................................................................................................................................................................19
Trip.............................................................................................................................................................................................19
Block..........................................................................................................................................................................................19
Reset. ........................................................................................................................................................................................19
Auto Reset. ................................................................................................................................................................................19
Panel-Reset. ..............................................................................................................................................................................19
Serial-Reset. ..............................................................................................................................................................................19
Remote-Reset............................................................................................................................................................................19
6.7.3. Restricted Earth Fault.......................................................................................................................................................................20
6.7.6. Serial Timeout..................................................................................................................................................................................20
6.7.7. Internal Error. ...................................................................................................................................................................................20
6.8. Trip History...............................................................................................................................................................................................21
6.9. Alarm History............................................................................................................................................................................................ 21
6.10. Last Five Faults. .....................................................................................................................................................................................21
6.11. Stats Info................................................................................................................................................................................................22
6.12. Calibration Menu. ...................................................................................................................................................................................22
6.13. Disturbance Recording (OPTIONAL). .....................................................................................................................................................23
7. Menu Tree Structure.........................................................................................................................................................................................24
8 MR-REF & MR-REF3 Setting Sheets.................................................................................................................................................................25
8.1. MR-REF & MR-REF3 System Settings Summary. .........................................................................................................................................25

MR
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Technical Manual
Issue 3, November 2013
8.2. MR-REF & MR-REF3 Control Setting Summary. ...........................................................................................................................................26
8.3. MR-REF & MR-REF3 Protection Setting Summary........................................................................................................................................27
8.4. MR-REF & MR-REF3 Blank Protection Setting Summary. ............................................................................................................................. 27
Appendix 1 ...........................................................................................................................................................................................................28
MR-REF – MR-REF3 Installation..........................................................................................................................................................................28
Appendix 2 ...........................................................................................................................................................................................................28
Termination Numbers MR-REF Version................................................................................................................................................................29
Appendix 3 ...........................................................................................................................................................................................................30
MR-REF Version Schematic Diagrams. ................................................................................................................................................................30
Version Appendix 4 ..............................................................................................................................................................................................31
Termination Numbers MR-REF3 Version..............................................................................................................................................................31
Appendix 5 ...........................................................................................................................................................................................................32
MR-REF3 Version Schematic Diagrams. ..............................................................................................................................................................32
Appendix 6 ...........................................................................................................................................................................................................33
Factory Default Procedure....................................................................................................................................................................................33
Appendix 7 ...........................................................................................................................................................................................................34
Handling Guidelines. ............................................................................................................................................................................................34

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Technical Manual
Issue 3, November 2013
1. P&B MR-REF & MR-REF3
P&B Protection Relay's MR-REF & MR-REF3 is a highly sophisticated microprocessor based feeder protection
relay, specifically designed to be used on low or medium voltage feeders as an integral part of any type or
manufacture of distribution equipment.
MR-REF & MR-REF3 monitors the earth current/s by means of conventional ring type current transformers with
typically 1A or 5A secondary outputs. This measured current is then used by the MR-REF & MR-REF3 to determine
tripping or alarm functions in order to interrupt the main switching device and protect the circuit or transformer from
damage.
The MR-REF & MR-REF3 is a withdrawable, easily installed package. The MR-REF & MR-REF3 with the 4 x relay
output option can be used as a replacement for older MREF relays by removing the relay module from the
switchgear mounted casing and fitting the new MR-REF & MR-REF3 in its place some wiring changes are required
to ensure compatibility.
All setting parameters are programmed independently for each unit via the integral keypad and liquid crystal display
on the front plate or via any of the communication ports and PC based software package available for the Vision
series of products.
During operational conditions the LCD also gives access to accurate load, statistical and fault data such as; Earth
Phase Amps, Time to Trip, In Service Hours, Number of operations.
Tri-Colour Light Emitting Diodes mounted on the front plate give immediate visual indication of the breaker status i.e.
HEALTHY / IRF / INHIBIT and ALARM / FAULTY / HEALTHY conditions.
The MR-REF & MR-REF3 can also be integrated onto an RS485 based network. This allows measured, statistical
and status information from the relay to be reported to a remote central communicating system.
Pages 25 to 27 can be used as a template for your relay settings schedule.

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1.1 Principle of operation
In the simple case above, for a current I
p
flowing through both CT’s will produce an equal secondary current. This
will flow around the loop and the voltage X-Y will remain zero and the MREF relay would not operate.
In the event of an internal (in zone) fault I
f
, only CT (A) would “see” this fault. The other CT (B) would appear as an
open circuit. Thus any secondary current in CT (A) would flow between X & Y operating the MREF.
In Practice, should this case become extremely large, one CT may saturate, in effect representing a shorted
secondary. In this case, the circulating current would produce a voltage across X/Y. Calculations must be made to
ensure stability under these circumstances, these are described in P&B application Note MR901
Unbiased Differential
Three MR-REF relays or one MR-REF3 are required to achieve full protection. Each with stabilizing resistors and
possibly a voltage dependent non-linear resistor.

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Restricted Earth Fault Protection for Transformers.
Application for 3 & 4 wire systems (System Earth at Switchboard)
Application for “5” wire systems (earth & Neutral connections both available at the transformer)

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1.2 Protective Functions.
Restricted Earth Fault Protection
Serial Timeout protection
Internal Error Protection
1.3 Displayed Feeder Data.
Restricted Earth Fault Current/s
No of Operations
Accumulated Current/s at Trip
Digital Input 1 Status
Digital Input 2 Status
Time to Trip
Healthy / Fault
Pick-up Phase
Alarm - Description - Pre-Alarm Values
Trip Description - Pre- Trip Values
1.4 Control Functions.
Via Hardwired inputs: Via Keypad Via Comms input:
Block, Reset Reset Reset

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2. Technical Specification.
Power Supply.
A UXILIARY P OWER S UPPLY & L OW V OLTAGE P OWER S UPPLY
AC Nominal Range 80 – 265V AC / DC
Range 24V AC / 24-48V DC (Low Voltage Power Supply Optional Extra)
Frequency 45 - 65 Hz
Maximum Power Consumption 10VA, 15VA Nominal
Measurement.
R ESTRICTED E ARTH P HASE C URRENT M EASUREMENT
Method True RMS, Sample time <1ms
Range 1.0 to 200% E/F CT Primary Amps
Full Scale 200% E/F CT Primary Amps Setting
Display Accuracy ±3% of Reading Over Range
Pick Up accuracy ±3% of setting
Protection Functions.
E ARTH F AULT T IME D ELAY
Earth Fault Trip 0.05 sec. for less than 1 second
Total Run Time Accuracy ±2%
T IME D ELAYS
Accuracy ±0.04 seconds
Exceptions
Earth Fault Trip +40mS,-0.0@ 1.1 x setting
+30mS,-0.0@ 2 x setting
+20mS,-0.0@ 5 x setting
Total Run Time Accuracy ±2%
Relay Contacts Ratings.
O UTPUT R ELAYS
Rated Load 10A @ 250 AC
10A @ 30V DC
Maximum Breaking Voltage 250V AC
Max Making Current (max. 4s at duty cycle 10%) 35A
Max Breaking Capacity AC 2500VA
Max Breaking Capacity DC 600mA @ 110V DC
100mA @ 220V DC

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3. Environmental Tests.
CLIMATIC
T
EST STANDARD
S
EVERITY LEVEL
Temperature Dry Cold
Operational
IEC 60068-2-1 -20 deg C ,96 hrs
Temperature Dry Cold
Transportation & Storage
IEC 60068-2-1 -40 deg C , 96hrs
Temperature Dry Heat
Operational
IEC 60068-2-2 +60 deg C , 96 hrs
Temperature Dry Heat
Transportation & Storage
IEC 60068-2-2 +85 deg C , 96 hrs
Damp Heat
Steady State
IEC 60068-2-30 95% Non-condensing, Cyclic Test Db
Enclosure IEC 60529 front IP52 , rear IP00
MECHANICAL
Vibration IEC 60255-21-1 Class I
Shock & Bump IEC 60255-21-2 Class I
Seismic IEC 60255-21-3 Class I
ELECTRICAL
Insulation resistance IEC 60255-5 500 Vdc , 5 secs
Dielectric Test IEC 60255-5 Series C of table 1
2.5 kV 50Hz , 1 min
1.0 kV open contacts , 1 min
High Voltage Impulse IEC 60255-5 5 kV peak 1.2/50uS,0.5J
3 pos , 3 neg
Voltage Dips , Short
Interruptions & Voltage
variations immunity
IEC 60255-11
IEC 61000-4-11
3 dips & 3 interruptions at 10 sec intervals of duration between 10mS
and 500mS at zero crossings. Variations 40% &70%
Ripple in dc supply IEC 60255-11 12% ac ripple
VT input Thermal
Withstand
120% Vn , continuous
CT input Thermal
Withstand
250xIn half wave,100xIn for 1 second 30 xIn for 10 second ,
4 xIn cont.
ELECTROMAGNETIC COMPATIBILITY
Electrical fast
Transient/Burst
IEC 60255-22-4
IEC 61000-4-4
Class IV-4.0kv Power supply
Class IV -4.0 kV Other inputs
1 min each polarity
Oscillatory Waves
1 Mhz Burst
IEC 60255-22-1 Class III
Longitudinal 2.5 kV , 2sec
Transverse 1.0 kV , 2 sec
Electrostatic Discharge IEC 60255-22-2 Class IV
8kV contact 15kV air discharge , 10 discharges at 1 sec intervals
Conducted Disturbance
RF fields
IEC 61000-4-6 0.15 to 80 Mhz
Severity Level 10Vrms
+sweeps 0.05-0.15MHz & 80-100MHz
Radiated e-m field
from digital portable
telephones
ENV 50204 900 & 1890mhz at 10V/m
Radiated RF e-m field
immunity test
IEC 60255-22-3 ClassIII test method A
+sweep 500-1000mhz
or IEC 1000-4-3 80-1000mhz
severity 10V/m 80% modulated 1 kHz
Surge Immunity IEC 61000-4-5 4kV common mode
4kV differential mode , 1.2/50uS
Power Frequency
Magnetic Field
IEC 61000-4-8 1000A/m for 1 sec
100A/m for 1 minute
Pulse Magnetic Field IEC 61000-4-9 6.4/16uS , 1000A/m
Damped Oscillatory
Magnetic Field Immunity
IEC 61000-4-10 0.1 & 1.0 Mhz , 100A/m
Conducted & Radiated RF
Interference Emission
EN55022 or
EN55011or
EN50081-2
Class A interference limits
Power frequency
conducted immunity,
common mode
IEC 61000-4-16
IEC 60255-22-7
DC to 150kHz sweep test level 4
300V at 16 2/3 & 50/60Hz

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4. Inputs and Outputs.
4.1. Power Supply Live.
The MR-REF & MR-REF3 requires a permanent AC or DC Voltage to supply the unit as specified by the relay rating
label. This auxiliary live is also used as the source voltage to power the digital inputs.
4.3. Current Transformer Inputs.
The MR-REF has provision to allow connection for one of standard protection class 1 amp or 5 amp secondary rated
current transformers with 1-2.5VA, or MR-REF-3 which allows for three standard protection class 1 amp or 5 amp
secondary rated current transformers with 1-2.5VA
4.4. Output Relays.
The MR-REF & MR-REF3 has 4 output relays which can be assigned depending upon the required function.
Each output relay is a changeover contact with Common (C) and Normally Open (NO) and Normally Closed (NC)
contacts.
4.5. Digital Inputs.
The MR-REF & MR-REF3 has 2 digital inputs which provide remote reset function and blocking input for the use
with protection functions.
The condition of all these inputs can be viewed at any time via the Display Scroll page of the relay, this enables
complete wire checking without the need to disconnect or even gain access to the rear panel wiring. The source
voltage for the digital inputs is derived from the auxiliary power supply, when power is connected, these terminals
may be live.
4.6. RS485 Rear Port.
The RS485 port utilises a half duplex RS485 protocol allowing up to 32 units to be daisy-chained together with a
single shielded twisted pair cable.
The host system can interrogate the unit to monitor status, running loads, historical data and fault data as well as
control functions such as reset of fault / alarm conditions. Setting parameters may also be changed or read.
The MR-REF & MR-REF3 is available with P&B network gold (P&B protocol) installed for use with the Xcell Data
Concentrator for fully Integrated Protection, Control & Monitoring Systems with full dual redundancy or with a Slave
implementation of Modbus RTU protocol for small systems and direct Modbus access to devices where data
concentration is not required.
4.7. RS232/USB Front Port.
The front mounted RS232/USB port allows access to historical and running data without disturbing the rear RS485
network. This port can be used for direct programming.

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5. Faceplate Functions.
The MR-REF & MR-REF3 faceplate has been designed to provide an intuitive easy to use display allowing access
to all the required information an operator would require.
This is achieved by using tri-colour LED indications and a LCD display driven by 4 function keys.
The concept eliminates the need for additional indication devices on the front of the feeder panel such as Lamps,
Ammeter, Voltmeter, Operations Counter, etc. Helping to reduce the overall cost of the panel and giving improved
reliability by the reduction of separate components.
5.1 LED Status
The LED's operate as follows:
LED Colour
Left Hand LED
–
Feeder
Status
Righ
t Hand LED
–
Fault Status
GREEN Healthy Healthy
AMBER Inhibit Alarm
RED IRF Fault
Feeder Settings
Y Top
Two line LCD Display
Selector button for
right hand menu
options
Up/Down Scroll keys.
For scrolling through
menus or increasing/
decreasing values
RS232/USB
Front Connection
Left Indicator
LED
“feeder status”
Selector button
for left hand
menu options
Right Indicator LED
“fault status”

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6. LCD Display.
The MR-REF & MR-REF3’s interface is fundamental to the philosophy of the Vision relay family of devices. The
screen provides access to all dynamic and historical data and protection parameters.
6.1. Menu Screens.
Upon power up the MR-REF & MR-REF3 software version screen appears for a few seconds. The screen shows the
software version and the unit type, which should be noted in all correspondence regarding the relay.
After the Introduction screen disappears then the initial display scroll page appears.
The four push buttons are used to navigate to areas of the menu structure.
Using these soft-keys provides for a very easy to use environment to effectively navigate the entire menu system.
Any description in the LCD window appearing to the
LEFT in CAPITALS can be selected using the left hand
push button.
Any description in the LCD window appearing to the
RIGHT in CAPITALS can be selected using the right
hand push button.
Otherwise the bottom right hand portion of the LCD is reserved for displaying status messages; such as, ACTIVE
FLT, E/F PKUP etc.
The centre push buttons are used to scroll the LCD
window to display different menu prompts or data.
Whilst the MENU prompt remains to the bottom left portion of the LCD, the up and down push buttons can be used
to select different pages of measured or status data, this is referred to as display scroll.
Any one of those display scroll pages can be selected as the default page, meaning if the unit is left in a sub menu –
it would automatically return to the pre-selected page within the display scroll after an adjustable period of time
SV100 MR
-
REF
SW Version
x.xxx
Iref 0.00A Hlth
MEN

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6.2. Display Scroll.
Examples of the Display Scroll screens.
The <UP> and<DOWN> buttons will allow each of the above screens to be displayed in turn returning to the first
screen and will loop continuously.
If a threshold is breached then the phase pick-up and function description will appear to the right hand portion of the
display. The lower half right hand side of the display will show which protective element has started to operate, <E/F
PKUP>.
If the relay pick-ups the right hand LED will pulse red at approximately once per second. If the relay picks up on a
high set function the same LED will pulse at a faster rate, flashing at approximately three times per second
Should the threshold breach(s) clear before the alarm or trip timers have expired then the message will
automatically clear and the LED will revert to its previous indication.
If a fault has occurred and subsequently cleared, then providing a panel reset has been configured the reset prompt
will appear in the lower portion of the display to the right hand side, displayed as <RST>.
Selecting the <MENU> button allows access in to the sub menu and settings structure. The <UP> and <DOWN>
buttons scroll through each sub menu heading.
The left button selects entry to each level. The right button <TOP> restores the screen to the display scroll and
menu prompt.
Iref 0.00A Hlth
MENU
DI1 OFF
MENU
DI2 OFF
MENU
Tr Restricted EF
MENU RST
Al No Alarm
MENU
Feeder Settings
YTop
Serial Settings
YTop
Iref 0.00A Hlth
MENU

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6.3. Feeder Settings.
This screen allows access to the Feeder Settings of the
relay. The EF CT Primary can be viewed and set.
The list of values that are available to be changed can
be scrolled through by pressing the UP and DOWN
buttons.
A value can be selected to have its value changed by pressing the Y button when the value is highlighted. This then
brings up the VALUE CHANGE SCREEN
The Value Change pop-up allows you to alter settings
in specified steps within the minimum and maximum
values of the particular setting range. The UP and
DOWN arrow buttons are used to alter the value. The
Next function is used to skip along to the next
character.
Save is pressed to store the new value and exit.
If an undesired value is inserted incorrectly use the Next button to skip past the last character to the left.
The Save option button now operates as a Discard to dump the new value without saving – reverting back
to the original value on initial selection.
E/F CT Primary.
This setting allows the user to program the primary current rating of the protection class current transformer used to
measure the earth fault current. It is assumed that all phase current transformers are of the same rating for the MR-
REF3

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6.4. Serial Settings.
This screen allows the configuration of the
communication ports.
Serial Enabled / Disabled.
This setting allows the user to enable the MR-REF & MR-REF3 serial communications port. This setting must be set
to ‘Enable’ if communication with the relay through any serial link is required.
Feeder Number.
This setting range 1 to 32, with a default setting of 1, identifies the MR-REF & MR-REF3 unit to the Xcell unit (or any
Master device connected to the Data highway) to which the RS485 port is connected. When updating firmware the
auto program mode requires the drive number to be 1.
RS485 Baud Rate.
This setting allows the user to configure the appropriate communications baud rate such that the MR-REF & MR-
REF3 can communicate effectively on the Data Highway to which it is connected.
RS485 Protocol.
The RS485 serial communications port may be configured to operate using a slave implementation of Modbus
RTU® or P&B’s own protocol “P&B Standard”.
RS485 Parity.
This setting allows the user to set the parity to match that of the host system on the serial link. The options are
“Odd”, “Even” and “None”.
RS232/USB Baud Rate.
This setting allows the user to configure the baud rate for the front mounted RS232/USB port.
RS232/USB Protocol.
The RS232/USB serial communications port may be configured to operate using Modbus RTU® or P&B’s own
protocol “P&B Standard”.
RS232/USB Parity.
This setting allows the user to set the parity to match that of the host system on the serial link. The options are
“Odd”, “Even” and “None”.
Serial Delay.
The MR-REF & MR-REF3 may be configured to respond to a request for information from the serial port instantly or
after a designated delay.
A communications delay may be beneficial to ensure the Master device on the Data Highway receives all
information sent back by the MR-REF & MR-REF3 without enduring data collisions on the network.
Serial Settings
YTop
Serial
YN
Enabled

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Fast Scan 1 to 3.
A Fast Scan is a system used when operating in conjunction with the XCell Data Concentrator. As the XCell polls
relays attached on its network, the fastscan settings allows the user to select important data to be read at a quicker
rate.
The data on the communications link is broken into Fast Scan Data (or Process Critical Data) and Slow Scan or Full
Read Data (Electrical Engineering Data).
The configuration of Fast Scan is not necessary unless the MR-REF & MR-REF3 in used in conjunction with the
XCell unit.
Each Fast Scan number can be programmed to export important data when requested. This number references an
internal address in MR-REF & MR-REF3 and allows configurable data mapping between units.
Max Scan Time.
This setting need only be used in order to limit the amount of data traffic on a RS485 network. Dynamic data can
change rapidly, this setting allows the MR-REF & MR-REF3 to limit the number of updates it makes to its Fast Scan
values.

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6.5. I/O Settings (Input / Output Settings).
The I / O settings are where the 2 digital inputs and 4
relay outputs are each assigned to a function.
Relay outputs can be assigned to the same function
where as the digital inputs cannot.
If a digital input has previously been assigned it is
removed from the list to prevent it being duplicated
elsewhere.
6.5.1 Digital Inputs
The MR-REF & MR-REF3 provides 2 digital inputs which can be configured to one of the functions described below.
Otherwise the digital input defaults are Not Used.
Reset Fault.
This input enables the operator to reset MR-REF & MR-REF3 Fault or Alarm conditions. The Input can only perform
a reset if the following conditions are met:
1. The Protection Settings for the specific fault or alarm are set to allow remote resets.
2. The condition that caused the Fault or Alarm to occur no longer exists.
Block.
The Block Input can be used to block assigned protection functions, upon energising of the Digital Input. Each
protection function has an option to enable the ‘BLOCK’ functionality. The block option must be configured in each of
the protection functions where blocking of the function may be desired in for the blocking input to work.
If a function is configured to be blocked AND the digital input assigned as block is energised, then that function is
prevented from taking its normal programmed action.
I / O Settings
YTop
Digital 1
YNReset Fault

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6.5.2 Relay Outputs
The MR-REF & MR-REF3 provides 4 changeover contact relay outputs, three of which can be configured to one of
the functions described below. Otherwise the programmable relay output defaults are Not Used. Relay 1 is fixed as
Trip
Trip.
If an output relay is assigned as ‘Trip’. Then this relay will change from the de-energised to the energised state when
triggered by any protection function that is configured to trip the relay.
Trip Fail Safe.
If an output relay is assigned as ‘Trip FS’ (Trip Failsafe). Then this relay will change from the energised to the de-
energised state when triggered by any protection function that is configured to trip the relay.
Alarm.
If an output relay is assigned as ‘Alarm’. Then this relay will change state from de-energised to the energised relay
contact when triggered by any protection function that is configured to alarm.
Alarm Fail Safe.
If an output relay is assigned as ‘Alarm FS’, then this relay will change state from energised to the de-energised
relay contact when triggered by any protection function that is configured to alarm.
Healthy.
If an output relay is assigned as ‘Healthy’, then this relay will be in its energised state at all times while the unit
reports the feeder as being healthy. This relay will be de-energised when the unit registers either an Alarm or Fault
condition.
Healthy Fail Safe.
If an output relay is assigned as ‘Healthy FS’, then this relay will be in its de-energised state at all times while the
unit reports the feeder as being healthy. This relay will be energised when the unit registers either an Alarm or Fault
condition.
Internal Fail. “Intrnl Fail”
If an output relay is assigned as ‘Intrnl Fail’, then this relay will energise if a hardware or software fault is detected by
the MR-REF & MR-REF3s internal diagnostic functions or watchdog circuits.
Serial Timeout. "Ser Timeout"
If an output relay is assigned as ‘Ser Timeout’, then this relay will energise if the relay does not receive any data
requests through the rear communication port

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6.6. System Settings.
This screen allows access to relay specific settings.
Such as, password functionality, screen contrast
settings etc. and non categorised relay settings.
These settings and their functions are explained in
detail below
Password.
If the password is set to enabled the default password (6363) may be used to change setting and reset statistical
data. If the password has been changed then the new password must be used.
Engineering Password
If enabled the Engineer Password will allow access using the standard password. Generally if a password is
requested a prompt will offer ‘AAAAA’, changing the second A to a B ‘ABAAA’ allows access.
Change Password.
The MR-REF & MR-REF3 default password is '6363'. It is recommended for security purposes this password is
changed. The password may be up to 6 characters long and alphanumeric if desired.
If the User Password is lost and the Engineers Password has been disabled the only options to retrieve the
password are to either read the information via the serial link or execute a Configuration Reset on the relay to
restore all of the factory defaults (see appendix 6).
Contrast and LCD Backlight.
These functions allow the user to change the display contrast and backlight levels.
Set Default Page / Default Return Time.
Any of the display scroll data pages can be nominated as the default page and returned to after a set period of key
press inactivity.
To set the page; select the required page in the main display scroll menu then enter the system settings menu and
select ‘set default page’.
Time Sync Delay.
The MR-REF & MR-REF3 can be time synchronised by either, Chronovision which is a GPS based device which
sits on the RS485 network and synchronises the time and date of each connected unit, or via broadcast command
on the daisy chained RS485 modbus network. This delay prevents immediate updating of the Relay real time clock
(RTC).
Software Version.
Displays the operating firmware loaded on to the unit. This should be noted along with the serial number when
corresponding about this equipment
Serial Number.
Displays the Serial number of the Relay.
System Settings
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Password
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