Bender ISOMETER isoPV425 with AGH420 User manual

Manual EN
ISOMETER® isoPV425
with AGH420 coupling evice
Insulation monitoring device for unearthed DC circuits (IT systems) for
photovoltaic systems up to 3(N)AC, AC 90 V / DC 1000 V
isoPV425_D00028_11_M_XXEN/07.2023

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ISOMETER® isoPV425
with AGH420 coupling device
Table of contents
1General information...........................................................................................5
1.1 How to use the manual.................................................................................................................................5
1.2 Indication of important instructions and information.......................................................................5
1.3 Signs and symbols...........................................................................................................................................5
1.4 Service and Support....................................................................................................................................... 5
1.5 Training courses and seminars...................................................................................................................5
1. Delivery conditions.........................................................................................................................................
1.7 Inspection, transport and storage.............................................................................................................
1.8 Warranty and liability.....................................................................................................................................
1.9 Disposal of Bender devices..........................................................................................................................
1.10 Safety.................................................................................................................................................................... 7
2Function...............................................................................................................8
2.1 Intended use......................................................................................................................................................8
2.2 Device features................................................................................................................................................. 8
2.3 Functional description...................................................................................................................................9
2.3.1 Monitoring the insulation resistance....................................................................................................... 9
2.3.2 Undervoltage/overvoltage monitoring................................................................................................ 10
2.3.3 Self test/error codes.....................................................................................................................................10
2.3.4 Malfunction......................................................................................................................................................11
2.3.5 Signalling assignment of the alarm relays K1/K2..............................................................................11
2.3. Measuring and response times................................................................................................................12
2.3.7 Password protection (on, OFF)................................................................................................................ 12
2.3.8 External test/reset button (T/R)............................................................................................................... 12
2.3.9 Fault memory..................................................................................................................................................13
2.3.10 History memory HiS..................................................................................................................................... 13
2.3.11 Interface/protocols........................................................................................................................................13
3Installation, connection an commissioning.................................................14
3.1 Dimensions...................................................................................................................................................... 14
3.2 Installation........................................................................................................................................................14
3.3 Connection.......................................................................................................................................................15
3.4 Commissioning...............................................................................................................................................1
4Operation.......................................................................................................... 18
4.1 Operating and display elements.............................................................................................................18
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Table of contents
4.2 Menu overview...............................................................................................................................................20
4.3 Displaying measured values..................................................................................................................... 20
4.4 Setting the response values (AL)............................................................................................................ 21
4.4.1 Setting the insulation resistance parameters.....................................................................................21
4.4.2 Setting parameters for undervoltage and overvoltage..................................................................22
4.4.3 Response values overview.........................................................................................................................22
4.5 Configuring fault memory, alarm relays, and interfaces (out)......................................................22
4.5.1 Configuring the relays.................................................................................................................................22
4.5.2 Allocating messages to the relays.......................................................................................................... 23
4.5.3 Activating or deactivating fault memory.............................................................................................23
4.5.4 Configuring interfaces.................................................................................................................................24
4. Setting delay times and self test cycles (t).......................................................................................... 24
4.7 Setting device control parameters (SEt)...............................................................................................24
4.8 Reset to factory settings.............................................................................................................................25
4.9 Showing and deleting the history memory........................................................................................25
4.10 Querying software version (InF).............................................................................................................. 25
5Data access via interfaces................................................................................26
5.1 Data access using the BMS protocol..................................................................................................... 2
5.2 IsoData data string....................................................................................................................................... 2
5.3 Data access using the Modbus RTU protocol.................................................................................... 27
5.3.1 Reading out the Modbus register from the ISOMETER®.................................................................27
5.3.2 Writing the Modbus register (parameter setting).............................................................................28
5.3.3 Exception code...............................................................................................................................................29
5.3.4 Modbus register assignment.................................................................................................................... 30
5.3.5 Device-specific data types......................................................................................................................... 33
6Technical ata...................................................................................................39
.1 Technical data isoPV425.............................................................................................................................39
.2 Technical data AGH420...............................................................................................................................43
.3 Standards and certifications..................................................................................................................... 4
.4 Ordering data..................................................................................................................................................4
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ISOMETER® isoPV425
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1 General information
1.1 How to use the manual
ADVICE
This manual is intended for qualified personnel working in electrical engineering and electronics!
Part of the device documentation in addition to this manual is the enclosed supplement "Safety
instructions for Bender products".
ADVICE
Read the operating manual before mounting, connecting and commissioning the device. Keep the
manual within easy reach for future reference.
1.2 In ication of important instructions an information
DANGER
Indicates a high risk of danger that will result in death or serious injury if not avoided.
WARNING
Indicates a medium risk of danger that can lead to death or serious injury if not avoided.
CAUTION
Indicates a low-level risk that can result in minor or moderate injury or damage to property if not
avoided.
Information can help to optimise the use of the product.
1.3 Signs an symbols
Disposal Protect from moisture Protect from dust
Temperature range Recycling RoHS directives
1.4 Service an Support
Information and contact details about customer service, repair service or field service for Bender devices are
available on the following website: Fast assistance | Bender GmbH & Co. KG.
1.5 Training courses an seminars
Regular face-to-face or online seminars for customers and other interested parties:
www.bender.de > know-how > seminars.
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General information
1.6 Delivery con itions
The conditions of sale and delivery set out by Bender GmbH & Co. KG apply. These can be obtained in printed
or electronic format.
The following applies to software products:
Die Elektroindustrie
‘Software clause in respect of the licensing of standard software as part of deliveries,
modifications and changes to general delivery conditions for products and services in the
electrical industry’
1.7 Inspection, transport an storage
Check the shipping and device packaging for transport damage and scope of delivery. In the event of
complaints, the company must be notified immediately, see "www.bender.de > service & support.".
The following must be observed when storing the devices:
1.8 Warranty an liability
Warranty and liability claims for personal injury and property damage are excluded in the case of:
•Improper use of the device.
•Incorrect mounting, commissioning, operation and maintenance of the device.
•Failure to observe the instructions in this operating manual regarding transport, commissioning, operation
and maintenance of the device.
•Unauthorised changes to the device made by parties other than the manufacturer.
•Non-observance of technical data.
•Repairs carried out incorrectly.
•The use of accessories or spare parts that are not provided, approved or recommended by the
manufacturer.
•Catastrophes caused by external influences and force majeure.
•Mounting and installation with device combinations not approved or recommended by the manufacturer.
This operating manual and the enclosed safety instructions must be observed by all persons working with the
device. Furthermore, the rules and regulations that apply for accident prevention at the place of use must be
observed.
1.9 Disposal of Ben er evices
Abide by the national regulations and laws governing the disposal of this device.
For more information on the disposal of Bender devices, refer to
www.bender.de > service & support.
isoPV425_D00028_11_M_XXEN/07.2023

ISOMETER® isoPV425
with AGH420 coupling device
1.10 Safety
If the device is used outside the Federal Republic of Germany, the applicable local standards and regulations
must be complied with. In Europe, the European standard EN 50110 applies.
DANGER Risk of fatal injury due to electric shock!
Touching live parts of the system carries the risk of:
•Risk of electrocution due to electric shock
•Damage to the electrical installation
•Destruction of the device
Before installing the device and before working on its connections, make sure that the installation
has been de-energised. The rules for working on electrical systems must be observed.
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Function
2 Function
2.1 Inten e use
The ISOMETER® monitors the insulation resistance RF of unearthed AC/DC main circuits (IT systems) with
nominal system voltages of 3(N)AC, AC/DC 0 … 90 V or DC 0 …1000 V.
DC components existing in 3(N)AC, AC/DC systems do not influence the operating characteristics when a
minimum load current of DC 10 mA flows. The separate supply voltage Us allows de-energised systems to be
monitored as well.
The ISOMETER® is always used in conjunction with the coupling device AGH420.
In order to meet the requirements of the applicable standards, customised parameter settings must be made
on the equipment in order to adapt it to local equipment and operating conditions. Please heed the limits of
the range of application indicated in the technical data.
Any other use or a use that goes beyond this constitutes improper use.
To ensure that the ISOM T R® functions correctly, an internal resistance of ≤ 1 kΩ must exist between L1/+
and L2/– via the source (e.g. the transformer) or the load.
If the ISOM T R® is installed inside a control cabinet, the insulation fault message must be audible and/or
visible to attract attention.
2.2 Device features
•Monitoring for unearthed AC and DC systems with galvanically connected rectifiers or frequency converters
•Measuring the nominal system voltage Un (true RMS) with undervoltage/overvoltage detection
•Selectable start-up delay, response delay and delay on release
•Measuring the residual voltages of the supply system to earth (L1/+, L2/– to PE)
•Automatic adaptation to the system leakage capacitance Ce up to 1000 μF
•Automatic device self test with connection monitoring
•Two separately adjustable response value ranges from 1…500 kΩ (alarm 1, alarm 2)
•Alarms output via LEDs ('AL1', 'AL2'), a display, and alarm relays ('K1', 'K2')
•Selectable N/C or N/O relay operation
•Measured value display via multi-functional LC display
•Fault memory can be activated
•Password protection against unauthorised changing of parameters
•RS-485 (galvanically isolated) including the following protocols:
– BMS (Bender measuring device interface) for the data exchange with other Bender devices
– Modbus RTU
– IsoData (for continuous data output)
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ISOMETER® isoPV425
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2.3 Functional escription
The ISOMETER® measures the insulation resistance RF and the system leakage capacitance Ce between the
system to be monitored (L1/+, L2/–) and earth (PE). The RMS value of the nominal system voltage Un between
L1/+ and L2/– as well as the residual voltages UL1e (between L1/+ and earth) and UL2e (between L2/– and earth)
are also measured.
From a minimum value of the nominal system voltage, the ISOMETER® determines the faulty conductor L1/+
or L2/–. The fault is indicated by a '+' or '–' sign preceding the measured value. The value range of the display is
±100 %:
Display Meaning
–100 % One-sided fault on conductor L2/–
0 % Symmetrical fault
+100 % One-sided fault on conductor L1/+
The partial resistances can be calculated from the total insulation resistance RF and the faulty conductor (R %)
using the following formula:
•Fault at con uctor L1/+: RL1F = (200 % * RF) / (100 % + R %)
•Fault at con uctor L2/–: RL2F = (200 % * RF) / (100 % – R %)
Also from a minimum value of the nominal system voltage, the ISOMETER® determines the insulation
resistance RUGF from the residual voltages UL1e and UL2e. It is an approximate value for one-sided insulation
faults and can be used as a trend indicator in cases where the ISOMETER® has to adapt to an RF and Ce relation
that varies considerably.
The determined fault can be assigned to an alarm relay via the menu. If the values RF or Un exceed the response
values activated in the 'AL' menu, this will be indicated by the LEDs and relays 'K1' and 'K2' according to the
alarm assignment set in the 'out' menu. In addition, the operation of the relay (n.o. / n.c.) can be set and the
fault memory 'M' can be activated.
If the values RF oder Un do not exceed their release value (response value plus hysteresis) for the period toff
without interruption, the alarm relays will switch back to their initial position and the alarm LEDs 'AL1'/'AL2'
stop lighting. If the fault memory is activated, the alarm relays remain in the alarm condition and the LEDs light
until the reset button 'R' is pressed or the supply voltage Us is interrupted.
The device function can be tested using the test button 'T'. Parameters are assigned to the device via the LCD
and the control buttons on the front panel; this function can be password-protected. Parameterisation is also
possible via the BMS bus, for example by using the BMS Ethernet gateway (COM4 5IP) or the Modbus RTU.
The isoPV425 determines the system leakage capacitance Ce through an impedance measurement whose
frequency is adjusted to the most accurate insulation measured value possible. The measurement signal is
affected if it goes through a rectifier or inverter. This can lead to phase errors that may result in an incorrect
system leakage capacitance value Ce.
2.3.1 Monitoring the insulation resistance
The insulation resistance RF is monitored by means of the parameters 'R1' (prewarning) and 'R2' (alarm) (see
chapter 4.4). The value 'R1' can only be set higher than the value 'R2'. If the insulation resistance RF reaches or
falls below the activated values 'R1' or 'R2', an alarm message will be signalled. If RF exceeds the values 'R1' or
'R2' plus the hysteresis value, the alarm will be cleared.
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Function
2.3.2 Un ervoltage/overvoltage monitoring
The two parameters ('U ˂' and 'U ˃') used to monitor the nominal system voltage Un can be enabled or
disabled in the response-value menu 'AL' (chapter 4.4). The maximum undervoltage value is limited by the
overvoltage value.
The RMS value of the nominal system voltage Un is monitored. If the nominal system voltage Un reaches,
falls below, or exceeds the limit values ('U ˂' and 'U ˃'), an alarm message will be signalled. If the maximum
permissible nominal system voltage Un set for the ISOMETER® is exceeded, an alarm message will be initiated
even when the overvoltage limit value has been deactivated. The alarm will be deleted when the limit values
plus hysteresis (chapter 4.4.1) are no longer violated.
2.3.3 Self test/error co es
The self test checks the function of the ISOMETER®, and monitors the connection to earth as well as the
connection to the system to be monitored. The alarm relays do not switch during an automatically started self
test. For a self test started manually, the switching of the alarm relays can be set using the parameter 'test' in
the alarm assignment (menu 'out', chapter 4.5.2). During the test, the display indicates 'tES'.
When malfunctions are detected or connections are missing, the LEDs 'ON'/'AL1'/'AL2' flash. The display shows
the respective error codes ('E.xx'), and in the factory setting relay 'K2' switches. The relays can be assigned to a
device error with the parameter 'Err' in the 'out' menu in the alarm assignment.
In the event of a device error, error co es are shown in the display. Some of these are described below:
Error code Meaning
E.01
PE connection error
The connection of E or KE to earth is interrupted.
Action: Check connection, eliminate error. The error code will be erased automatically once the
error has been eliminated.
E.02
System connection error
The internal resistance of the system is too high or the connection of L1/+ or L2/– to the system is
interrupted. The terminals L1/+ and L2/– are connected incorrectly.
Action: Check connection, eliminate error. The error code will be erased automatically once the
error has been eliminated.
E.05
Measurement error
Due to system interferences or a device error, the insulation measured value is no longer updated.
Prewarning and alarm are set for the insulation measured value at the same time.
Calibration invalid after software update
E.05 appears together with E.08 : The software is not compatible to the calibration of the device.
Action: Install the previous software version or have the device calibrated at the factory.
E.07
Permissible system leakage capacitance Ce e ceeded
The device is not suitable for the present network leakage capacitance Ce.
Action: Uninstall the device.
E.08 Calibration error
Action: Check connection, eliminate error. If the error is still present, there is a device error.
Internal device errors 'E.xx' can be caused by external disturbances or internal hardware errors. If the error
message occurs again after the device has been restarted or after a reset to the factory settings (menu item
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ISOMETER® isoPV425
with AGH420 coupling device
'FAC'), the device must be repaired. After the fault has been eliminated, the alarm relays switch back either
automatically or when the reset button is pressed. The self test can take a few minutes.
2.3.3.1 Automatic self test
In the factory setting a self test is carried out when the supply voltage Us is connected and after that every 24 h.
This cycle can be adjusted: off, 1 h, 24 h (see chapter 4. ).
The self test can be suppressed for the device start so that the device can enter the measurement mode more
quickly. To this end, set the parameter 'S.Ct = off' in the menu 'SEt'.
2.3.3.2 Manual self test
The manual self test is started by pressing the external test/reset button or the test button 'T' on the device for
˃ 1.5 s. Holding the test button 'T' also shows all display elements.
2.3.3.3 Connection monitoring
Connection monitoring, activated by the self test, checks the connections of terminals 'E' and 'KE' to the
protective earth conductor (PE). When an error is detected, the message device error ('Err') will be signalled
and the error code 'E.01' appears on the display.
The system connection monitoring checks the connection of terminals 'L1/+' and 'L2/–' to the system to be
monitored. When an interruption or a high-resistance connection between L1/+ and L2/– is detected via the
internal resistance of the system, the device error ('Err') is signalled and the error code 'E.02' appears on the
display. Since a test of the system connection may take considerable time due to system disturbances or may
even provide incorrect results, the system connection monitoring can be disconnected using the parameter
'nEt' in the 'SEt' menu.
2.3.4 Malfunction
The device checks some of its functions continuously during operation. If a fault is detected, the device
error ('err') will be signalled, 'E.xx' appears on the display as an identifier for error type xx, and the LEDs
'ON'/'AL1'/'AL2' will flash.
Please contact Bender Service, if the error occurs again after the device has been restarted or the factory
settings have been restored.
2.3.5 Signalling assignment of the alarm relays K1/K2
The notifications for 'device error', 'insulation fault', 'undervoltage/overvoltage fault', 'device test' and 'device
start with alarm' can be assigned to the alarm relays via the 'out' menu.
An insulation fault is indicated by the messages '+R1', '–R1', '+R2' and '–R2'. Messages '+R1' and '+R2' indicate
an insulation fault assigned to conductor L1/+, and the messages '–R1' and '–R2' indicate an insulation
fault assigned to conductor L2/–. If an assignment to a conductor is not possible, e.g. due to a symmetrical
insulation fault, the respective '+' and '–' messages are set together.
The message 'test' indicates a evice test.
The message 'S.AL' indicates a evice start with alarm. When the parameter value is set to 'S.AL = on' and the
supply voltage Us is connected, the ISOMETER® starts with the insulation measured value RF = 0 Ω and sets all
activated alarms. The alarms will be cleared only when the measured values are up-to-date and no thresholds
are exceeded. In the factory setting 'S.AL = off', the ISOMETER® starts without an alarm.
isoPV425_D00028_11_M_XXEN/07.2023 11

Function
Recommendation: Set parameter value 'S.AL' identical for both relays.
2.3.6 Measuring an response times
Operating time tae
The operating time tae is the time required by the ISOMETER® to determine the measured value. For the
insulation measured value RF, the system leakage capacitance Ce, the residual voltages UL1e and UL2e as well
as for the faulty conductor L1/+ or L2/- it is dependent on the insulation resistance RF and the system leakage
capacitance Ce. System disturbances may lead to extended measuring times. The measuring time of the
nominal system voltage Un is independent of this and significantly shorter.
Response elay ton
The response delay ton is set uniformly for all messages in the 't' menu using the parameter 'ton', while
each alarm message specified in the alarm assignment has its own timer for ton. This delay can be used for
interference suppression in the case of short measuring times.
An alarm will only be signalled when a threshold value of the respective measured value is violated for the
duration of ton without interruption. Every time the threshold value is violated within the time ton, the response
delay 'ton' restarts once again.
Total response time tan
The total response time tan is the sum of the operating time tae and the response delay ton.
Delay on release toff
The delay on release toff can be set uniformly for all messages using the parameter 'toff', while each alarm
message specified in the alarm assignment has its own timer for toff.
An alarm will continue to be signalled until the threshold value of the respective measured value is no longer
violated (including hysteresis) for the duration of toff without interruption. Each time a threshold value is no
longer violated during toff, the delay on release 'toff' restarts once again.
Start-up elay t
After connecting the supply voltage US, the alarm output is suppressed for the time set in parameter
‘t’ (0…10 s).
2.3.7 Passwor protection (on, OFF)
If password protection is activated (on), settings can only be made after entering the password (0...999). For its
activation, see chapter 4.7.
2.3.8 External test/reset button (T/R)
Functions
•Reset = press the external button < 1.5 s
•Reset + self test = press the external button > 1.5 s
•Stop measuring function = press and hold the external button
When the measuring function is stopped, the display shows 'StP'.
The stop function can also be triggered via an interface command, and in this case it can only be reset via the
interface.
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ISOMETER® isoPV425
with AGH420 coupling device
Only one ISOMETER® may be controlled via an external test/reset button.
A galvanic parallel connection of several test or reset inputs for testing multiple insulation monitoring devices
is not allowed.
2.3.9 Fault memory
Disable (OFF)
The LEDs and relays signal the fault as long as it is detected.
Enable (ON)
The LEDs and relays signal the fault until a reset is performed or the supply voltage Us is disconnected.
2.3.10 History memory HiS
The history memory saves exclusively the measured values for the first fault. The history memory must first be
cleared before new measured values can be saved.
The values checked in the table in chapter 4.3 can be saved.
2.3.11 Interface/protocols
The ISOMETER® uses the serial hardware interface RS-485 with the following protocols:
•BMS
The BMS protocol is an essential component of the Bender measuring device interface (BMS bus protocol).
Data transmission generally makes use of ASCII characters.
•Mo bus RTU
Modbus RTU is an application layer messaging protocol, and it provides master/slave communication
between devices that are connected via bus systems and networks. Modbus RTU messages have a 1 -bit
CRC (cyclic redundant checksum), which guarantees reliability.
•IsoData
The ISOMETER® sends an ASCII data string with a cycle of approximately 1 second. Communication with
the ISOMETER® in this mode is not possible, and no additional sender may be connected via the RS-485 bus
cable. The ASCII data string for the ISOMETER® is described in chapter 5.2.
The parameter address, baud rate and parity for the interface protocols are configured in the 'out' menu.
With 'Adr = 0', the menu entries baud rate and parity are not shown in the menu and the IsoData protocol
is activated.
With a valid bus address (i.e. not equal to 0), the menu item 'baud rate' is displayed in the menu. The
parameter value '---' for the baud rate indicates the activated BMS protocol. In this case, the baud rate
for the BMS protocol is set to 9600 baud. If the baud rate is set unequal to '---', the Modbus protocol with
configurable baud rate is activated.
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Installation, connection and commissioning
3 Installation, connection an commissioning
3.1 Dimensions
3
93
74.5
90 45 70.5
47.5
31.1
Figure: Dimension diagram (in mm)
3.2 Installation
Figure: DIN rail mounting (left) or screw mounting (right)
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ISOMETER® isoPV425
with AGH420 coupling device
3.3 Connection
For details about the required conductor cross sections, refer to the technical data from Technical data
isoPV425.
Figure: Wiring diagram
CAUTION Danger from touching hot surfaces!
If the AGH420 is operated at mains voltages > 800 V, the temperature of the enclosure may exceed 60 °C.
•Once the device is connected to the mains voltage, avoid touching the surfaces of the device.
isoPV425_D00028_11_M_XXEN/07.2023 15

Installation, connection and commissioning
Wiring diagram legend:
Terminal Connections
A1, A2 Connection to the supply voltage Us via a fuse:
If supplied from an IT system, both lines have to be protected by a fuse.*
E, E, KE Connect each terminal separately to PE:
Use the same wire cross section as for A1 , A2 .
L1/+, L2/– Connection to the 3(N)AC, AC or DC system to be monitored
Up, AK1, GND, AK2 Connect the terminals of the AGH420 to the corresponding terminals of the ISOMETER®.
T/R Connection for external combined test and reset button
11, 14 Connection to alarm relay K1
11, 24 Connection to alarm relay K2
A, B RS-485 communication interface with selectable terminating resistance
* For UL applications:
Only use 60/75 °C copper lines!
UL and CSA applications require the supply voltage Us to be protected via 5 A fuses.
3.4 Commissioning
1. Check that the ISOMETER® is properly connecte to the system to be monitored.
2. Connect supply voltage Us to the ISOMETER®.
The device carries out a calibration, a self test and adjusts itself to the IT system to be monitored. With
high system leakage capacitances this process may take up to 4 min. The standard display then appears
showing the present insulation resistance, e.g.:
The pulse symbol signals an error-free update of the resistance and capacitance measured values. If the
measured value cannot be updated due to disturbances, the pulse symbol will be blanked.
The voltage of the IT system to be monitored can also be selected as standard display: Select measured
value display UL1L2 with the up and down buttons and accept with ENTER.
3. Start a manual self test by pressing the test button 'T'. Whilst the test button is pressed and held down
for > 1.5 s, all display elements available for this device are shown. During the test, the 'tES' symbol flashes.
Any internal malfunctions detected are shown on the display as error codes (see chapter 2.3.3.1). The
alarm relays are not checked during the test (factory setting). The setting can be changed in the 'out' menu
so that the relays switch to the alarm state during the manual self test.
4. Check factory setting for suitability.
Are the settings suitable for the installation to be monitored?
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ISOMETER® isoPV425
with AGH420 coupling device
The list of factory settings is shown in the tables from chapter 4.4.
5. Check the function using a genuine insulation fault.
Check the ISOMETER® against earth in the system being monitored, e.g. via a suitable resistance.
isoPV425_D00028_11_M_XXEN/07.2023 17

Operation
4 Operation
4.1 Operating an isplay elements
Device front Operating elements Function
ON Device is running
AL1 Prewarning
Overvoltage
AL2 Alarm
Undervoltage
Up and down buttons
– For navigating up or down in the
menu settings.
– For increasing or decreasing values.
TTest button (press >1.5s)
RReset button (press >1.5s)
Enter button
– Select menu item.
– Save value.
MENU MENU button (press >1.5s)
– Starts menu mode.
– Exits menu item without saving
changes.
LED on
LED flashes
The 'prewarning' and 'alarm' messages can be assigned to the relays, see chapter 4.5.2.
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ISOMETER® isoPV425
with AGH420 coupling device
Display Display elements Function
UNominal system voltage Un
IAmperage In
RInsulation resistance RF
ZImpedance ZF
CSystem leakage capacitance Ce
L1 L2 Monitored conductors
Voltage type DC
Pulse symbol: error-free measured
value update
Voltage type AC
auto Automatic self test active
°C
μ n F Hz
k M Ω %
m V A s
Measured values and units
Password protection is activated
In the menu mode, the operating
mode of the respective alarm relay is
displayed.
Adr Communication interface with
measured value: isoData operation
MFault memory is activated
on / off Condition symbols
test Self test is active
>
+
<
Identification for response values and
response value violation
The display parameters that can be configured flash.
isoPV425_D00028_11_M_XXEN/07.2023 19

Operation
4.2 Menu overview
Measurement isplay Menu selection Parameter selection
Menu item Parameter
AL Querying and setting response values
out Configuring fault memory, alarm relays and interface
tSetting delay times and self test cycles
SEt Setting device control parameters
InF Querying software version
HiS Querying and clearing the history memory
ESC Going to the next-higher menu level
4.3 Displaying measure values
Overview
HiS Display Description
✓± R kΩ Insulation resistance
1 kΩ … 1 MΩ
RF
Resolution 1 kΩ
✓C µF System leakage capacitance
1 µF … 1105 µF
Ce
Resolution 1 µF
20 isoPV425_D00028_11_M_XXEN/07.2023