Bender ISOMETER isoHV425 User manual

Manual EN
ISOMETER® isoHV425 with
AGH422 coupling device
Insulation monitoring device for unearthed AC, AC/DC and
DC systems (IT systems) up to 3(N)AC, AC 1000 V
Software version: D0453 V1.xx (isoHV425-D4-4)
D0500 V1.xx (isoHV425-D4M-4)
isoHV425_D00082_02_M_XXEN/05.2020

Bender GmbH & Co. KG
Londorfer Str. 65 • 35305 Grünberg • Germany
PO Box1161 • 35301 Grünberg • Germany
Tel.: [phone] • Fax: [phone]
E-mail: [e-mail] • www.bender.de
©Bender GmbH & Co. KG
All rights reserved.
Reprinting only with permission of the publisher.
Subject to change!
Photos: Bender archive.

3
Table of contents
isoHV425_D00082_03_M_XXEN/05.2020
1. Important information ........................................................................... 6
1.1 How to use this manual ................................................................................... 6
1.2 Technical support: service and support .................................................... 7
1.2.1 First Level Support ............................................................................................ 7
1.2.2 Repair Service ..................................................................................................... 7
1.2.3 Field Service ......................................................................................................... 8
1.3 Training courses ................................................................................................. 8
1.4 Delivery conditions ........................................................................................... 8
1.5 Inspection, transport and storage ............................................................... 8
1.6 Warranty and liability ....................................................................................... 9
1.7 Disposal ................................................................................................................. 9
2. Safety instructions ................................................................................ 10
2.1 General safety instructions .......................................................................... 10
2.2 Work activities on electrical installations ................................................ 10
2.3 Intended use ..................................................................................................... 11
3. Function .................................................................................................. 12
3.1 Device features ................................................................................................. 12
3.2 Functional description .................................................................................. 12
3.2.1 Monitoring of the insulation resistance .................................................. 13
3.2.2 Undervoltage/overvoltage monitoring .................................................. 14
3.2.3 Self test/error codes ....................................................................................... 14
3.2.4 Signalling assignment of the alarm relays K1/K2 ................................ 16
3.2.5 Measuring and response times .................................................................. 17
3.2.6 Password protection (on, OFF) ................................................................... 18
3.2.7 Factory setting FAC ......................................................................................... 18
3.2.8 External, combined test or reset button T/R ......................................... 18
3.2.9 Fault memory .................................................................................................... 18
3.2.10 History memory HiS ........................................................................................ 18
3.2.11 Digital interfaces (isoHV425-D4-4) ........................................................... 19
3.2.12 Analogue interface (isoHV425-D4M-4) .................................................... 19

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4isoHV425_D00082_03_M_XXEN/05.2020
4. Mounting, connection and commissioning .....................................20
4.1 Mounting ............................................................................................................ 20
4.2 Wiring diagram ................................................................................................. 22
4.2.1 Connection isoHV425-D4-4 ......................................................................... 22
4.2.2 Connection isoHV425W-D4M-4 with analogue interface: ................ 23
4.3 Commissioning ................................................................................................ 25
5. Operation ................................................................................................26
5.1 Display elements ............................................................................................. 27
5.2 Menu overview ................................................................................................. 28
5.3 "AL" menu – response value setting ........................................................ 29
5.4 "out" menu ......................................................................................................... 29
5.4.1 Configuration of the relay operating mode ........................................... 29
5.4.2 Relay signalling assignment "r1" and "r2" and LED assignment ..... 30
5.4.3 Fault memory configuration ...................................................................... 30
5.4.4 Interface configuration (isoHV425-D4-4) ............................................... 31
5.4.5 Analogue output (isoHV425-D4M-4) ........................................................ 31
5.5 "t" menu – time configuration ................................................................... 32
5.6 "SEt" menu – function configuration ........................................................ 32
5.7 Measured value display and history memory ....................................... 33
6. BMS protocol (isoHV425-D4-4) ...........................................................34
7. Modbus RTU protocol (isoHV425-D4-4) ............................................35
7.1 Reading out the Modbus register from the ISOMETER® .................... 35
7.1.1 The master sends a command to the ISOMETER® ............................... 35
7.1.2 The ISOMETER® answers the master ......................................................... 35
7.2 Writing to Modbus registers (parameter setting) ................................ 35
7.2.1 The master sends a command to the ISOMETER® ............................... 36
7.2.2 The ISOMETER® answers the master ......................................................... 36
7.3 Exception code ................................................................................................. 36
7.4 Modbus register assignment ...................................................................... 37
7.5 Device-specific data types ............................................................................ 40
7.5.1 Device name ...................................................................................................... 40
7.5.2 Measured values .............................................................................................. 40
7.5.3 Alarm assignment of the relays .................................................................. 43
7.5.4 Channel descriptions ..................................................................................... 44

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isoHV425_D00082_03_M_XXEN/05.2020
8. IsoData data string (isoHV425-D4-4) ................................................ 45
9. Technical data ....................................................................................... 46
9.1 Tabular presentation ...................................................................................... 46
9.2 Standards .......................................................................................................... 51
9.3 Ordering information ..................................................................................... 51
INDEX ........................................................................................................... 52

6isoHV425_D00082_03_M_XXEN/05.2020
1. Important information
1.1 How to use this manual
Always keep this manual within easy reach for future reference.
To make it easier for you to understand and revisit certain sections of text and
instructions in this manual, we have used symbols to identify important instructions
and information. The meaning of these symbols is explained below:
This manual is intended for qualified personnel working in electrical engi-
neering and electronics!
DANGER
This signal word indicates that there is a high risk of danger that will
result in death or serious injury if not avoided.
WARNING
This signal word indicates a medium risk of danger that can lead to
death or serious injury, if not avoided.
CAUTION
This signal word indicates a low-level risk that can result in minor or
moderate injury or damage to property if not avoided.
This symbol denotes information intended to assist the user in
making optimum use of the product.

Important information
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isoHV425_D00082_03_M_XXEN/05.2020
1.2 Technical support: service and support
For commissioning and troubleshooting Bender offers:
1.2.1 First Level Support
Technical support by phone or e-mail for all
Bender products
 Questions about specific customer applications
 Commissioning
 Troubleshooting
Telephone: [phone]**
Fax:[phone]
In Germany only:0700BenderHelp (telephone and fax)
E-mail: [email protected]
1.2.2 Repair Service
Repair, calibration, update and replacement service for Bender products
 Repair, calibration, testing and analysis
 Hardware and software update
 Delivery of replacement devices for faulty or incorrectly delivered Bender devices
 Extended warranty for Bender devices with in-house repair service or replace-
ment devices at no extra cost
Telephone: [phone]** (technical issues)/
[phone]**, -785** (commercial issues)
Fax: [phone]
E-mail: [email protected]
Please send the devices for repair to the following address:
Bender GmbH, Repair-Service,
Londorfer Str. 65,
35305 Grünberg

Important information
8isoHV425_D00082_03_M_XXEN/05.2020
1.2.3 Field Service
On-site service for all Bender products
 Commissioning, parameter setting, maintenance, troubleshooting
 Analysis of the electrical installation in the building (power quality, EMC, ther-
mography)
 Practical training courses for customers
Telephone: [phone]**, -762 ** (technical issues)/
[phone]** (commercial issues)
Fax: [phone]
E-mail: [e-mail]
Internet: www.bender.de
*365 days 7.00 a.m. – 8.00 p.m. (CET/UTC +1)
**Mo-Thu 7.00 a.m. – 4.00 p.m., Fr 7.00 a.m. – 1.00 p.m
1.3 Training courses
Bender is happy to provide training regarding the use of test equipment. Current dates
of training courses and workshops can be found on the Internet at: www.bender.de/en
–> Know-how –> Seminars
1.4 Delivery conditions
The conditions of sale and delivery set out by Bender apply.
For software products, the "Softwareklausel zur Überlassung von Standard- Software
als Teil von Lieferungen, Ergänzung und Änderung der Allgemeinen Lieferbedingun-
gen für Erzeugnisse und Leistungen der 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) set out
by the ZVEI (Zentralverband Elektrotechnik- und Elektronikindustrie e.V., (German Elec-
trical and Electronic Manufacturers' Association) also applies.
Conditions of sale and delivery can be obtained from Bender in printed or electronic for-
mat.
1.5 Inspection, transport and storage
Check the shipping and device packaging for damage and compare the package con-
tents with the shipping documents. In case of transport damage, please notify Bender
immediately.
The devices must only be stored in areas where they are protected from dust,
humidity and spray or dripping water, and in which the specified storage temperatures
can be assured.

Important information
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isoHV425_D00082_03_M_XXEN/05.2020
1.6 Warranty and liability
Warranty and liability claims for personal injury and property damage are excluded if
they are attributable to one or more of the following causes:
 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 manufac-
turer.
 Non-observance of technical data.
 Repairs carried out incorrectly and the use of spare parts or accessories not rec-
ommended by the manufacturer.
 Catastrophes caused by external influences and force majeure.
 Mounting and installation with device combinations not recommended by the
manufacturer.
This operating manual, especially the safety instructions, must be observed by all per-
sons working with the device. Furthermore, the rules and regulations that apply for ac-
cident prevention at the place of use must be observed.
1.7 Disposal
Abide by the national regulations and laws governing the disposal of this device. Ask
your supplier if you are not sure how to dispose of the old equipment.
The directive on waste electrical and electronic equipment (WEEE directive) and the di-
rective on the restriction of certain hazardous substances in electrical and electronic
equipment (RoHS directive) apply in the European Community. In Germany, these pol-
icies are implemented through the "Electrical and Electronic Equipment Act" (ElektroG).
According to this, the following applies:
 Electric and electronic equipment are not to be included in household waste.
 Batteries and accumulators are not to be included in household waste but must
be disposed of in accordance with the regulations.
 Old electrical and electronic equipment from users other than private households
which was introduced to the market after 13 August 2005 will be taken back by
the manufacturer and disposed of properly.
For more information on the disposal of Bender devices, refer to our
homepage at www.bender.de/en –> Service & support.

10 isoHV425_D00082_03_M_XXEN/05.2020
2. Safety instructions
2.1 General safety instructions
In addition to these operating manual, the "Safety instructions for Bender products",
which are also included in the scope of supply, are an integral part of the device docu-
mentation.
2.2 Work activities on electrical installations
If the device is being used in a location outside the Federal Republic of Germany, the
applicable local standards and regulations must be complied with. European standard
EN 50110 can be used as a guide.
DANGER
Risk of electrocution due to electric shock!
Touching live parts of the system carries the risk of:
 An electric shock
 Damage to the electrical installation
 Destruction of the device
Before installing and connecting the device, make sure that the
installation has been de-energised. Observe the rules for working on
electrical installations.

Important information
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isoHV425_D00082_03_M_XXEN/05.2020
2.3 Intended use
The ISOMETER® monitors the insulation resistance RFof unearthed AC, AC/DC and DC
systems (IT systems) with system voltages of 3(N)AC, AC/DC 0…1000 V or DC 0…1000
V. The maximum permissible system leakage capacitance Ceis 150 µF. DC components
existing in AC systems do not influence the operating characteristics when a minimum
load current of DC 100 mA flows. The separate supply voltage Usallows de-energised
systems to be monitored as well.
In order to meet the requirements of applicable standards, the equipment must be ad-
justed to local equipment and operating conditions by means of customised parameter
settings. Please heed the limits of the range of application indicated in the technical da-
ta.
Any use other than that described in this manual is regarded as improper..
Only qualified personnel are permitted to carry out the work
necessary to install, commission and run a device or system.
To ensure that the ISOMETER® functions correctly, an internal system
resistance of
≤ 1 kΩ must exist between L1/+ and L2/- via the source
(e.g. the transformer) or the load.
In the event of an alarm message of the ISOMETER®, the insulation
fault should be eliminated as quickly as possible.
If the ISOMETER® is installed inside a control cabinet, the insulation
fault message must be audible and/or visible to attract attention.

12 isoHV425_D00082_03_M_XXEN/05.2020
3. Function
3.1 Device features
 Monitoring the insulation resistance RFfor unearthed AC/DC systems
 Measurement of the system voltage Un(True RMS) with undervoltage and over-
voltage detection
 Measurement of the DC residual voltages system to earth (L1+/PE and L2-/PE)
 Automatic adaptation to the system leakage capacitance Ceup to 150 F
 Selectable start-up delay, response delay and delay on release
 Two separately adjustable response value ranges from 10…500 k
 Alarm signalling 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
 Measured value indication via a multi-functional LC display
 Fault memory can be activated
 Password protection to prevent unauthorised parameter changes
isoHV425-D4-4
 RS-485 (galvanically separated) including the following protocols:
– BMS interface (Bender measuring device interface) for data exchange with
other Bender components
– Modbus RTU
– IsoData (for continuous data output)
isoHV425-D4M-4
 Analogue output (galvanically separated)
3.2 Functional description
The ISOMETER® measures the insulation resistance RFand the system leakage capaci-
tance Cebetween the system to be monitored (L1/+, L2/-) and earth (PE). The RMS value
of the system voltage Unbetween L1/+ and L2/-, as well as the DC residual voltages UL1e
(between L1/+ and earth) and UL2e (between L2/- and earth) are also measured.
From a minimum DC system voltage, the ISOMETER® determines the faulty conductor
L1/+ or L2/-, i.e. the distribution of the insulation resistance between the conductors L1/
+ and L2/-, and indicates this by means of a positive or negative sign preceding the
measured insulation resistance value. The value range of the faulty conductor is ±100
%:

Important information
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isoHV425_D00082_03_M_XXEN/05.2020
The partial resistances can be calculated from the total insulation resistance RFand the
faulty conductor (R %) using the following formula:
 Fault on conductor L1/+ –>RL1F = (200 % * RF)/(100 % + R %)
 Fault on conductor L2/- –> RL2F = (200 % * RF)/(100 % – R %)
It is possible to assign the detected fault or the faulty conductor to an alarm relay via the
menu. If the values RFor Unviolate the response values activated in the "AL" menu, this
will be indicated by the LEDs and relays K1 and K2 according to the signalling assign-
ment set in the "out" menu. In addition, the operation of the relay (n.c./n.o.) can be set
and the fault memory "M" can be activated.
If the values RFor Undo not violate 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 go out. If the fault memory is activated, the alarm
relays remain in alarm condition and the LEDs light until the reset button "R" is pressed
or the supply voltage Usis 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 a BMS Ethernet gateway (COM465IP) or Modbus
RTU.
3.2.1 Monitoring of the insulation resistance
The two parameters "R1" and "R2" for monitoring the insulation resistance RFcan be
found in the response value menu "AL" (see table on Page 29). The value "R1" can only
be set higher than the value "R2". If the insulation resistance RFreaches or falls below
the activated values "R1" or "R2", this leads to an alarm message. If RFexceeds the values
"R1" or "R2" plus the hysteresis value (see table on Page 29), the alarm will be cleared.
Display Meaning
-100 % One-sided fault on conductor L2/-
0 % Symmetrical fault
+100 % One-sided fault on conductor L1/+
The isoHV425 determines the system leakage capacitance Cevia an
impedance measurement the frequency of which is adjusted to an
insulation measurement that is as accurate as possible. The
measuring signal is influenced by rectifiers or inverters and phase
errors may occur, resulting in a distorted measured value for the
system leakage capacitance Ce.

Important information
14 isoHV425_D00082_03_M_XXEN/05.2020
3.2.2 Undervoltage/overvoltage monitoring
In the response value menu "AL" (see Page 29), the two parameters ("U <" and
"U >") for monitoring the system voltage Uncan be activated or deactivated. The maxi-
mum undervoltage value is limited by the overvoltage value.
The r.m.s. value of the system voltage Unis monitored. If the system voltage Unreaches,
falls below or exceeds the limit values ("U <"or"U>"), an alarm will be signalled. If the
maximum permissible system voltage Unset for the ISOMETER® 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 (see Page 29) are no longer
violated.
3.2.3 Self test/error codes
The isoHV425xx contains test routines for checking that the device is functioning cor-
rectly during operation. Some test routines are performed cyclically or continuously in
the background during the normal measuring function. Other test routines are trig-
gered by the user. The following options are available to the user:
 cyclically via a timer (menu item "t" / "test")
 via the internal test button
 via the external test button
 via the communication interface (COM)
In case of a device error, all 3 LEDs on the device flash, the display shows the message
"E.xx" according to the following error code table and depending on the signalling as-
signment, the relays switch.

Important information
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isoHV425_D00082_03_M_XXEN/05.2020
Error codes
If a device error occurs, the following error codes appear on the display:
Internal device errors "E.xx" can be caused by external disturbances or internal hard-
ware errors. If the error message occurs again after restarting the device or after a reset
to factory settings (menu item "FAC") , the device must be repaired.
After eliminating the error, the alarm relays switch back automatically or by pressing
the reset button. The self test can take a few minutes.
It can be suppressed for the duration of the device start by setting the parameter in the
menu "SEt" to "S.Ct = off". This allows the ISOMETER® to enter measurement mode
quickly after connecting the supply voltage Us.
Error code Description
E.01
PE connection error
The connection of terminals 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, the connection of terminals
L1/+ or L2/- to the system is interrupted or L1/+ and
L2/- are connected with reversed polarity to the monitored DC system (Un< –
100 V).
Action:
Check connection, eliminate error. The error code will be erased automatically
once the error has been eliminated.
E.05 Measurement technology error/calibration invalid
For the current software version
E.07
The maximum permissible system leakage capacitance Ceaccording to the
technical data is exceeded
Action:
Device not suitable for the existing system leakage capacitance Ce:
uninstall device.
E.08
Calibration error during device test
Action:
If the error continues to exist after checking the device connections, there is an
error inside the device.

Important information
16 isoHV425_D00082_03_M_XXEN/05.2020
Cyclic background test
The cyclic background test to check the functionality of the µC 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.
If the error occurs again after restarting the device or after a reset to factory settings,
contact Bender Service.
Continuous PE connection monitoring
The connection of terminal E of the AGH to the PE protective conductor is monitored
continuously and in parallel with the measuring function of the device via the input KE
of the isoCHA425HV, which is also connected to the PE protective conductor. In case of
a connection interruption, the device error message "E.01" is displayed.
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 (device error "E.05") and addition-
ally a test of the connection between the terminals L1/+ and L2/- via the system to be
monitored (device error system connection "E.02") which can be activated by the user
(menu "SEt" / "nEt"). If during the system connection check a system voltage Unnega-
tive DC -100 VDC is applied to the ISOMETER®, the message "E.02" for a system connec-
tion with reversed polarity is also displayed.
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").
3.2.4 Signalling assignment of the alarm relays K1/K2
The messages "Device error", "Insulation fault", "Undervoltage/overvoltage fault, "De-
vice test" or "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". The
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/-.
The message "test" indicates a self test.
The message "S.AL" indicates a so-called "device start with alarm". After connecting to
the supply voltage Usand setting the parameter to "S.AL = on", the ISOMETER® starts
with the insulation measured value RF= 0  and sets all activated alarms. The alarms are
only cleared when the measured values are up-to-date and no thresholds are violated.
With the factory setting "S.AL = off", the ISOMETER® starts without an alarm. It is recom-
mended to set the parameter value "S.AL" identically for both relays.

Important information
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isoHV425_D00082_03_M_XXEN/05.2020
3.2.5 Measuring and response times
The measuring time is the time required to detect a measured value. The measuring
time is reflected in the operating time tae. The measuring time for the measured insula-
tion resistance value is mainly determined by the required measuring pulse duration,
which depends on the insulation resistance RFand the system leakage capacitance Ce
of the system to be monitored. The measuring pulse is produced by the measuring
pulse generator integrated in the ISOMETER®. The measuring times for Ce, UL1e, UL2e
and R % are synchronous. System disturbances may lead to extended measuring times.
In contrast, the time for the system voltage measurement Unis independent and con-
siderably shorter.
Total response time tan
The total response time tan is the sum of the operating time tae and the response delay
time ton.
Operating time tae
The operating time tae is the time required by the ISOMETER® to determine the meas-
ured value. For the measured insulation resistance value, it depends on the insulation
resistance RFand the system leakage capacitance Ce.
Response delay ton
The response delay ton is set uniformly for all messages in the "t" menu using the param-
eter "ton", whereby each alarm message specified in the signalling assignment has its
own timer for ton. This delay time 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 val-
ue is violated for the period of ton without interruption. Every time the threshold value
is violated within the time ton, the response delay "ton" restarts once again.
Delay on release toff
The delay on release toff can be set uniformly for all messages in the "t" menu using the
parameter "toff", whereby each alarm message listed in the signalling assignment hast
its own timer for toff. An alarm will continuously be signalled until the threshold value
of the respective measured value is not violated (including hysteresis) for the period of
toff without interruption. Each time the threshold value is not violated for the period of
toff, the delay on release "toff" restarts.
Start-up delay t
After connection to the supply voltage Usthe alarm indication is supressed for the pre-
set time (0…10 s) specified for parameter "t".

Important information
18 isoHV425_D00082_03_M_XXEN/05.2020
3.2.6 Password protection (on, OFF)
If password protection has been activated (on), settings can only be made if the correct
password has been entered (0...999).
3.2.7 Factory setting FAC
Activating the factory settings will reset all modified settings ? with the exception of the
interface parameters ? to the default values upon delivery.
3.2.8 External, combined test or reset button T/R
Reset= press the external button < 1.5 s
Reset followed by a test = press the external button > 1.5 s
Stop measuring function = press and hold the external button
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 ISOMETER® may be controlled via an external test/reset button. A galvanic
parallel connection of several test or reset inputs for testing multiple insulation moni-
toring devices is not allowed.
3.2.9 Fault memory
The fault memory can be activated or deactivated with the parameter "M" in the "out"
menu. When the fault memory is activated, all pending alarm messages of the LEDs and
relays remain available until they are deleted by using the reset button (internal/exter-
nal) or the supply voltage Usis turned off.
3.2.10 History memory HiS
When the first error occurs after clearing the history memory, all measured values (that
are marked in the table on Page 33) are saved in the history memory. This data can be
read out using the menu item "HiS". In order to be able to record a new data record, the
history memory must first be cleared via the menu using "Clr".

Important information
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isoHV425_D00082_03_M_XXEN/05.2020
3.2.11 Digital interfaces (isoHV425-D4-4)
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 is transferred using ASCII characters.
 Modbus RTU
Modbus RTU is an application layer messaging protocol and it provides master/slave
communication between devices that are connected altogether via bus systems and
networks. Modbus RTU messages have a 16-bit CRC (Cyclic Redundant Checksum),
which guarantees reliability.
 IsoData
The ISOMETER® continously sends an ASCII data string with a cycle of approximately 1
s. Communication with the ISOMETER® within this mode is not possible and no addi-
tional transmitter may be connected to the RS-485 bus cable. The ASCII data string for
the ISOMETER® is described on Page 45.
The parameter address, baud rate and parity for the interface protocols are configured
in the "out" menu.
3.2.12 Analogue interface (isoHV425-D4M-4)
The following functions can be selected at the potential-free analogue signal output:
 Voltage output DC 0…10 V
 Current output DC 4…20 mA
 Current output DC 0…20 mA
 Current output DC 0…400 µA
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 event, the baud rate for the
BMS protocol is set to 9,600 baud. If the baud rate is set unequal to "---",
the modbus protocol is activated with a configurable baud rate.

20 isoHV425_D00082_03_M_XXEN/05.2020
4. Mounting, connection and commissioning
4.1 Mounting
 DIN rail mounting:
Snap the mounting clip at the rear of the device onto the DIN rail so that it sits
securely.
 Screw mounting:
Use a tool to position the rear mounting clips so that they project beyond the
enclosure (a second mounting clip is required, see ordering information). Fix the
device with two M4 screws (see the following sketch).
Only qualified personnel are permitted to carry out the work
necessary to install, commission and run a device or system.
DANGER
Risk of electrocution due to electric shock!
Touching live parts of the system carries the risk of:
 An electric shock
 Damage to the electrical installation
 Destruction of the device
Before installing and connecting the device, make sure that the
installation has been de-energised. Observe the rules for working
on electrical installations.
If the ISOMETER® is used in rail vehicles, it must be ensured that the
ISOMETER® is installed in a control cabinet which meets the fire
protection requirements of DIN EN 45545-2.