Bender ISOMETER isoCHA425 User manual

Manual EN
ISOMETER® isoCHA425
Insulation monitoring device
For unearthed DC systems 0 V to 400 V
Suitable for DC charging stations according to CCS or CHAde O
Software version: D0612 V4.xx
isoCHA425_D00352_03_M_XXEN/08.2023

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ISO ETER® isoCHA425
Table of contents
1General information 5
1.1 How to use this 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
1.6 Delivery conditions......................................................................................................................................... 6
1.7 Inspection, transport and storage.............................................................................................................6
1.8 Warranty and liability.....................................................................................................................................6
1.9 Disposal of Bender devices..........................................................................................................................6
1.10 Safety.................................................................................................................................................................... 7
2Function 8
2.1 Intended use......................................................................................................................................................8
2.2 Device features................................................................................................................................................. 8
2.3 Functional description...................................................................................................................................9
2.3.1 RF and Ce in 'CHd' mode (CHAde O)...................................................................................................... 9
2.3.2 RF and Ce in 'dc' mode (CCS).................................................................................................................... 10
2.3.3 Fault location R%.......................................................................................................................................... 10
2.3.4 System leakage capacitance Ce............................................................................................................... 10
2.3.5 System voltages Un, UL1e and UL2e.......................................................................................................... 10
2.3.6 Functional tests of contactors in the charging station and the vehicle....................................10
2.3.7 onitoring the insulation resistance.....................................................................................................11
2.3.8 Undervoltage/overvoltage monitoring................................................................................................ 11
2.3.9 Stop mode....................................................................................................................................................... 11
2.3.10 Self test functions (device errors)........................................................................................................... 11
2.3.11 Alarm assignment of the alarm relays K1/K2..................................................................................... 13
2.3.12 Fault memory..................................................................................................................................................13
2.3.13 Digital interfaces............................................................................................................................................14
2.3.14 easuring and response times................................................................................................................14
2.3.15 Password protection (on, OFF)................................................................................................................ 15
2.3.16 External test/reset button (T/R)............................................................................................................... 15
2.3.17 History memory HiS..................................................................................................................................... 15
3Installation, connection and commissioning 16
3.1 Dimensions...................................................................................................................................................... 16
isoCHA425_D00352_03_ _XXEN/08.2023 3

Table of contents
3.2 Installation........................................................................................................................................................16
3.3 Connection.......................................................................................................................................................16
3.4 Commissioning...............................................................................................................................................18
4Operation 19
4.1 Operating and display elements.............................................................................................................19
4.2 enu overview...............................................................................................................................................21
4.3 Displaying measured values..................................................................................................................... 22
4.4 Setting the response values (AL)............................................................................................................ 23
4.4.1 Response values overview.........................................................................................................................23
4.4.2 Setting the insulation resistance parameters.....................................................................................23
4.4.3 Setting parameters for undervoltage and overvoltage..................................................................23
4.5 Configuring fault memory, alarm relays, and interfaces (out)......................................................24
4.5.1 Configuring the relays.................................................................................................................................24
4.5.2 Assigning the alarm messages to the relays...................................................................................... 24
4.5.3 Activating or deactivating fault memory.............................................................................................25
4.5.4 Configuring interface...................................................................................................................................25
4.6 Setting delay times and self test cycles (t).......................................................................................... 26
4.7 Setting device control parameters (SEt)...............................................................................................26
4.8 Reset to factory settings.............................................................................................................................27
4.9 Showing and deleting the history memory........................................................................................27
4.10 Querying software version (InF).............................................................................................................. 27
5Data access via RS-485 interface 28
5.1 Data access using the B S protocol..................................................................................................... 28
5.2 Data access using the odbus RTU protocol.................................................................................... 28
5.2.1 Reading out the odbus register from the ISO ETER®.................................................................28
5.2.2 Writing the odbus register (parameter setting).............................................................................29
5.2.3 Exception code...............................................................................................................................................30
5.3 odbus register assignment.................................................................................................................... 31
5.3.1 odbus measured value registers......................................................................................................... 31
5.3.2 odbus parameter register...................................................................................................................... 34
5.4 IsoData data string....................................................................................................................................... 37
6Technical data 39
6.1 Technical data isoCHA425......................................................................................................................... 39
6.2 Standards and certifications..................................................................................................................... 44
6.3 Ordering data..................................................................................................................................................44
6.4 Document revision history........................................................................................................................ 45
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ISO ETER® isoCHA425
1 General information
1 1 How to use this 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 Indication of important instructions and 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 and symbols
Disposal Protect from moisture Protect from dust
Temperature range Recycling RoHS directives
1 4 Service and 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 and seminars
Regular face-to-face or online seminars for customers and other interested parties:
www.bender.de > know-how > seminars.
isoCHA425_D00352_03_ _XXEN/08.2023 5

General information
1 6 Delivery conditions
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 and 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 and 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.
•ounting 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 Bender devices
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.
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ISO ETER® isoCHA425
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.
isoCHA425_D00352_03_ _XXEN/08.2023 7

Function
2 Function
2 1 Intended use
The ISO ETER® monitors the insulation resistance RF for DC fast charging stations according to CHAde O
standard or according to Combined Charging System (CCS) for nominal system voltage ranges between DC 0 V
and 400 V.
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 ISO ETER® functions correctly, an internal resistance of ≤ 1 kΩ must exist between L+
and L– via the source (e.g. the transformer) or the load.
If the ISO ETER® is installed inside a control cabinet, the insulation fault message must be audible and/or
visible to attract attention.
2 2 Device features
•onitoring of the insulation resistance RF of DC charging stations in accordance with the CHAde O
standard or Combined Charging System (CCS)
•CHAde O ( ode CHd):
– aximum system leakage capacitance 1.6 μF per conductor
– Detection of insulation faults in the system voltage range from 50 V to 400 V
– Response time for one-pole insulation faults RFU:
•RFU ≤ 100 kΩ: max. 1 s
•100 kΩ < RFU ≤ 2 Ω: max. 10 s
– Response time for two-pole insulation faults RFS: max. 10 s
•CCS ( ode dc):
– Detection of insulation faults up to 2 Ω
– aximum system leakage capacitance Ce: 5 μF
– Response time tan at Ce ≤ 5 μF or RF ≤ 100 kΩ: max. 10 s
•easuring the system leakage capacitance Ce
•easuring the nominal system voltage Un (True-R S) with undervoltage/overvoltage detection
•easuring the residual voltages UL1e (between L+ and earth) and UL2e (between L– and earth)
•Selectable start-up delay, response delay and delay on release
•Two separately adjustable response value ranges from 5…250 kΩ (prewarning, alarm)
•Alarm output via LEDs ('AL1', 'AL2'), display, and alarm relays ('K1', 'K2')
•Automatic device self test with connection monitoring
•Selectable N/C or N/O relay operation
•easured value indication via multi-functional LC display
•Activatable fault memory
•RS-485 (galvanically isolated) including the following protocols:
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ISO ETER® isoCHA425
– B S (Bender measuring device interface) for the data exchange with other Bender devices
– odbus RTU
– IsoData (for continuous data output)
•Password protection against unauthorised changing of parameters
•Stop mode to disable the measuring pulse generator
2 3 Functional description
The ISO ETER® is designed for use in DC charging stations according to CHAde o standard or Combined
Charging System (CCS) and can be set to the respective mode in the 'SEt' menu via the ode parameter.
It measures
•the total insulation resistance RFS;
•the one-sided insulation resistance RFU;
•the system leakage capacitance Ce;
•the system voltage Un (True R S) between L+ and L–
•the DC system voltages (residual voltages) UL1e and UL2e between L+ as well as L– and earth.
RFS and RFU are combined to the value RF. For RF a prewarning and an alarm limit value can be set in the 'AL'
menu. The prewarning limit value can only be set higher than the alarm limit value. If the measured value
reaches or falls below the limit values, an alarm is signalled. For the measured value Un an overvoltage and
undervoltage limit value can be enabled and adjusted, the violation of which triggers an alarm. The limit
value alarms are deleted when the respective measured value no longer violates the limit value including the
corresponding hysteresis.
All alarms generated by the ISO ETER® are signalled via the LEDs 'AL1' and 'AL2'. In the 'out' menu, the alarms
can be assigned to the alarm relays ('K1', 'K2'). In addition, the operation of the alarm relays (n.o./n.c.) can
be configured and the fault memory ' ' can be activated or deactivated. If the fault memory is activated,
the alarm relays remain in alarm condition until the reset button 'R' is pressed or the supply voltage Us is
interrupted.
In the 't' menu, the start-up delay at device start, the response delay and the delay on message release as well
as the repetition time of the automatic device self test can be set.
For the RS-485 interface, the protocols B S, odbus RTU or isoData are selected in the 'out' menu. The
measured values can be read and the parameters of the ISO ETER® can be set via the B S protocols, e.g. using
the B S Ethernet gateway (CO 465IP) and odbus RTU. If the isoData protocol is selected, the ISO ETER®
only sends the measured values, once per second.
The device function can be tested using the test button 'T'.
The device parameters are set via the LC display and via the control buttons on the front panel. This function
can be password-protected.
The ISO ETER® can be set to stop mode to deactivate the measuring pulse generator.
2 3 1 RF and Ce in 'CHd' mode (CHAdeMO)
The insulation fault RF and the system leakage capacitance Ce are only determined for DC system voltages
≥ 50 V. The maximum permissible system leakage capacitance Ce is 1.6 μF per conductor. In mode 'CHd'
the value RF is determined by the smaller of the values RFU and RFS. RFU is the one-pole total insulation fault
determined from the voltages UL1e and UL2e up to a maximum of 2 Ω.
isoCHA425_D00352_03_ _XXEN/08.2023 9

Function
RFS is the two-pole total insulation fault. It is determined up to a maximum of 2 Ω.
The response time of the one-pole insulation fault RFU is one second for RFU ≤ 100 kΩ and Un ≥ 50 V. For values
RFU > 100 kΩ as well as RFS, the response time of RF is ≤ 10 s.
2 3 2 RF and Ce in 'dc' mode (CCS)
The insulation fault RF up to 2 Ω and the system leakage capacitance Ce are determined independently of the
system voltage. The maximum permissible system leakage capacitance is 5 μF . The response time for RF is 10 s.
2 3 3 Fault location R%
From Un > DC 20 V the fault location R% is calculated for insulation faults RF up to 500 kΩ ('CHd' mode 150 kΩ).
Value Meaning
–100 % one-pole insulation fault at L–
0 % symmetrical insulation fault
+100 % one-pole insulation fault at L+
For values of 30 % and more, the alarm assignment of the relays distinguishes between insulation faults at L+
and L–.
From the values R% and RF the partial resistances RF+ and RF– can be calculated using the following formulas:
•Fault at conductor DC+: RF+ = (200 % x RF) / (100 % + R%)
•Fault at conductor DC–: RF– = (200 % x RF) / (100 % – R%)
2 3 4 System leakage capacitance Ce
The system leakage capacitance Ce is determined for insulation faults RF > 10 kΩ up to a value of 17 μF. Above
12 μF, the message Device error 'E.07' is displayed.
For applications according to UL 2231-1/-2, the system leakage capacitance Ce is limited to 5 μF.
2 3 5 System voltages Un, UL1e and UL2e
The system voltage Un between terminals L+ and L– is measured as R S value (True-R S). Limit values for
overvoltage and undervoltage are available in the 'AL' menu (see 'Setting the response values (AL)'). Above
510 V, the message 'Overvoltage' is displayed regardless of the set overvoltage limit value.
The DC system voltages UL1e and UL2e are respectively measured between terminals L+ as well as L– and earth.
No limit value is assigned to them.
2 3 6 Functional tests of contactors in the charging station and the vehicle
If the ISO ETER® is disconnected on one pole from the monitored voltage source during a functional test of
the charging station or vehicle contactors, a false alarm may occur depending on the location of an existing
insulation fault. For insulation faults above 250 kΩ the false alarm can be prevented by a resistor of 200 kΩ
connected directly between the terminals L+ and L–.
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ISO ETER® isoCHA425
2 3 7 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 is triggered. If RF exceeds the values 'R1' or 'R2'
plus the hysteresis value, the alarm will be cleared.
2 3 8 Undervoltage/overvoltage monitoring
To monitor the nominal system voltage Un, the two parameters 'U ˂' and 'U ˃' can be enabled in the response-
value menu 'AL' (chapter 4.4). The maximum undervoltage value is limited by the overvoltage value.
The R S 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 will be signalled. If the maximum permissible
nominal system voltage Un set for the ISO ETER® is exceeded, an alarm message will be triggered even if the
overvoltage limit value has been deactivated. The alarm will be deleted when the limit values plus hysteresis
(chapter 4.4.2) are no longer violated.
2 3 9 Stop mode
For applications where the ISO ETER® is not needed and the measuring pulse interferes with other measuring
functions, it can be set to stop mode via the odbus protocol or by pressing and holding the external test/
reset button ('T/R'). The measuring pulse generator is turned off and the measuring function is deactivated.
The message 'StP' appears on the display. It sends the identifiers 'warning' and 'external test' via the
communication interface.
The L+ and L- connections disconnect from the monitored mains. The electronic circuit breakers are in the
device.
2 3 10 Self test functions (device errors)
During the normal measuring function the ISO ETER® checks its correct function in the background.
Other tests interrupt the the measuring function of the device. The user can trigger these as follows:
•cyclically via a timer (menu item 't' / 'test') or
•via the internal or external test button or
•via the communication interface (CO )
In case of a device error, all LEDs flash, the display shows the message 'E.xx' according to the error code table
and, depending on the message assignment, the relays switch.
Cyclic background test
The cyclic background test checks the functionality of the μC. It is not visible to the user and does not influence
the measuring function. In case of malfunction, the respective device error messages 'E.09' to 'E.16' appear.
Continuous PE connection monitoring
The connection of terminal 'E' to the PE protective conductor is monitored continuously and in parallel with
the measuring function of the device via the input 'KE', which is also connected to the PE protective conductor.
When the connection is interrupted, the device error message 'E.01' appears.
isoCHA425_D00352_03_ _XXEN/08.2023 11

Function
User-controlled test functions
The user-controlled test functions interrupt the measuring function of the device. They always include a test
of the measurement technology (error code 'E.05') and additionally a test of the connection between the
terminals L+ and L– via the system to be monitored (error code 'E.02') which can be activated by the user
(menu 'SEt' / 'nEt').
If these test functions are started via a test button or the communication interface, this can be indicated not
only by the LEDs AL1 and AL2 lighting up but also by the message 'test' via the relays (menu 'out' / 'Signalling
assignment').
Internal and external test button
Pressing the external test/reset button or the test button 'T' on the device (> 1.5 s) starts the user-controlled
test functions. Holding the test button 'T' on the device also shows all available display elements.
Timer for test functions
At menu item 't'/'test' the user-controlled test can be activated in a cycle of one or 24 hours. The timer restarts
after each completed test, regardless of whether it was triggered by the timer or manually.
Device test at device start
At menu item 'SEt'/'S.Ct' the user-controlled test functions can be activated for device start.
System connection test
The system connection test configurable in the menu 'SEt'/'nEt' checks the connection between the terminals
L+ and L– via the monitored system. For the ISO ETER® to function correctly, the monitored system must have
a low internal resistance Ri < 1 kΩ.
If an error is detected, the message Device error system connection 'E.02' appears. If the System voltage Un
is below DC –30 V during the mains connection test, the message Device error polarity reversal 'E.03' also
appears.
Error codes
In the event of a device error, error codes are shown in the display. Some of these are described below:
Overview of some error codes
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.0
System connection error
The internal resistance of the system is too high or the connection of 'L+' or 'L–' to the system is
interrupted. The terminals 'L+' and 'L–' are connected incorrectly.
Action: Check connection, eliminate error. The error code will be erased automatically once the
error has been eliminated.
E.03
Reversed polarity connection error
Terminals 'L+' and 'L–' are connected to the DC system to be monitored with reversed polarity.
Detection from Un ˂ DC –30 V
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ISO ETER® isoCHA425
Error code Meaning
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
'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 11 Alarm 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 these messages:
•'+R1' and '+R2': insulation fault assigned to conductor L+
•'–R1' and '–R2': insulation fault assigned to conductor L–
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 device test triggered manually via a test button or the communication interface.
The message 'S.AL' indicates a device start with alarm. When the parameter value is set to 'S.AL = on' and the
supply voltage Us is connected, the ISO ETER® 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 violated. In the factory setting 'S.AL = off', the ISO ETER® starts without an alarm.
Recommendation: Set parameter value 'S.AL' identical for both relays.
2 3 12 Fault memory
Disabled (OFF)
The LEDs and relays signal the fault as long as it is detected.
Enabled (ON)
The LEDs and relays signal the fault until a reset is performed or the supply voltage Us is disconnected.
isoCHA425_D00352_03_ _XXEN/08.2023 13

Function
2 3 13 Digital interfaces
The ISO ETER® uses the serial hardware interface RS-485 with the following protocols:
•BMS
The B S protocol is an essential component of the Bender measuring device interface (B S bus protocol).
Data transmission generally makes use of ASCII characters.
•Modbus RTU
odbus RTU is an application layer messaging protocol, and it provides master/slave communication
between devices that are connected via bus systems and networks. odbus RTU messages have a 16-bit
CRC (cyclic redundant checksum), which guarantees reliability.
•IsoData
The ISO ETER® sends an ASCII data string with a cycle of approximately 1 second. Communication with
the ISO ETER® 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 ISO ETER® is described in chapter 5.4.
The IsoData protocol can be terminated by sending the command 'Adr3' during a transmission pause of
the ISO ETER®.
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 B S protocol. In this case, the baud rate
for the B S protocol is set to 9600 baud. If the baud rate is set unequal to '---', the odbus protocol with
configurable baud rate is activated.
2 3 14 Measuring and response times
Operating time tae
The operating time tae is the time required by the ISO ETER® 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 'R%' it depends 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 delay ton
The response delay ton is set uniformly for all alarm 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 message will only be signalled when a limit value of the respective measured value is violated for the
duration of ton. Each time the limit value is violated within the time ton, the response delay 'ton' restarts.
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
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ISO ETER® isoCHA425
The delay on release toff can be set uniformly for all alarm messages using the parameter 'toff', while each alarm
message specified in the alarm assignment has its own timer for toff.
An alarm message will be signalled until the limit value of the respective measured value is no longer violated
(including hysteresis) for the duration of toff without interruption. Each time a limit value is no longer violated
during toff, the delay on release 'toff' restarts.
Start-up delay t
After connecting the supply voltage US, the alarm output is suppressed for the time set in parameter
't' (0…10 s).
2 3 15 Password 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 16 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.
Only one ISO ETER® 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 17 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 section 'Displaying measured values' can be saved.
isoCHA425_D00352_03_ _XXEN/08.2023 15

Installation, connection and commissioning
3 Installation, connection and commissioning
3 1 Dimensions
36
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)
3 3 Connection
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.
For details about the conductor cross sections required for wiring, refer to chapter "6 Technical data".
16 isoCHA425_D00352_03_ _XXEN/08.2023

ISO ETER® isoCHA425
Wiring diagram
AC
DC
US
KE
A1
A2
14
24 11
K1
K2
Test / Reset
COM465IP
RS-485
E
6 A
6 A
DC+
DC-
PE
A
B
R
L-
L+
T/R
ON AL1 AL2 k
T R MENU
Ron
off
14 24 11
AT/R
B
L+
L-
E KE A2A1
Figure: Wiring diagram
Legend to wiring diagram
Terminal Connections
A1, A2 Connection to the supply voltage Us via fuse (line protection):
If supplied from an IT system, protect both lines by a fuse.*
E, KE Connect each terminal separately to PE:
Use same wire cross section as for 'A1', 'A '.
L+, L– Connection to the system to be monitored
Indication in display: 'L1' for L+; 'L ' for L-
T/R Connection for the external combined test and reset button
11, 14 Connection to alarm relay 'K1'
11, 24 Connection to alarm relay 'K '
A, B RS-485 communication interface with connectable terminating resistor
Example: Connection of a BMS Ethernet gateway COM465IP
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Installation, connection and commissioning
* For UL applications:
Use 60/70 °C copper lines only!
For UL and CSA applications, using 5A fuses for the protection of the supply voltage Us is mandatory.
3 4 Commissioning
1. Check that the ISOMETER® is properly connected to the system to be monitored
2. Connect supply voltage Us to the ISOMETER®
The start routine can take up to 30 s. Afterwards, the current insulation resistance is shown as the standard
display.
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.
3. Set the correct insulation monitoring mode in the 'SEt' menu. The factory setting is 'CHd'.
4. Start a manual self test by pressing the test button 'T' > 1.5 s. While holding the test button all available
display elements are shown. After releasing the button, the test starts and ‘tES’ flashes for the duration of
the test. Detected malfunctions are displayed as error codes (see chapter 2.3.11).
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.
5. Check if the settings are suitable for the system being monitored
The list of factory settings is shown in the tables from chapter 4.4.
For networks with a leakage capacitance > 5 μF, the response value Ran1 should be set to a maximum
of 200 kΩ due to the increased measurement tolerance.
6. Check the functionality by a real insulation fault
Use a suitable resistor to check the ISO ETER® against earth in the system being monitored.
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ISO ETER® isoCHA425
4 Operation
4 1 Operating and display 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.
isoCHA425_D00352_03_ _XXEN/08.2023 19

Operation
Display Display elements Function
UNominal system voltage Un
RInsulation resistance RF
CSystem leakage capacitance Ce
L1 L2 Monitored conductors
L1 = L+
L = L–
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.
The readability below –25 °C is limited.
Depending on the ISO ETER®'s scope of functions, not all display elements are used.
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