Bender ISOMETER isoES425 User manual

EN
Manual
Insulation monitoring device for
unearthed AC, AC/DC and DC systems (IT systems) for
energy storage devices
up to AC/DC 400 V
Software version: D0471 V1.xx
ISOMETER® isoES425
isoES425_D00214_00_M_XXEN/01.2019

Bender GmbH & Co. KG
P.O. Box 1161 • 35301 Gruenberg • Germany
Londorfer Strasse 65 • 35305 Gruenberg • Germany
Tel.: [phone]
Fax: [phone]
E-mail: [email protected]
Web: www.bender.de
© Bender GmbH & Co. KG
All rights reserved.
Reprinting only with permission
of the publisher.
Subject to change!
Customer service
Service hotline: 0700-BenderHelp (Telephone and Fax)
Carl-Benz-Strasse 8 • 35305 Gruenberg • Germany
Tel.:[phone]
Fax:[phone]
E-mail:[e-mail]
READ THIS MANUAL AND ALL ACCOMPANYING DOCUMENTS CAREFULLY
AND RETAIN FOR FUTURE REFERENCE.

3
isoES425_D00214_00_M_XXEN/01.2019
1. Important information ..................................................................... 5
1.1 How to use this manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Technical support: Service and support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.1 First level support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.2 Repair service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.3 Field service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3 Training courses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4 Delivery conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 Inspection, transport and storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6 Warranty and liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.7 Disposal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2. Safety instructions ............................................................................ 8
2.1 General safety instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Work activities on electrical installations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3. Function .............................................................................................. 9
3.1 Device features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.1 Monitoring of the insulation resistance . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.2 Undervoltage/overvoltage monitoring . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.3 Self test/error codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.4 Connection monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.5 Malfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.6 Alarm assignment of the alarm relays "K1"/"K2" . . . . . . . . . . . . . . . . 11
3.2.7 Measuring and response times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.8 Password protection (on, OFF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2.9 Factory settings FAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2.10 External, combined test or reset button T/R . . . . . . . . . . . . . . . . . . . 12
3.2.11 Fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2.12 History memory HiS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2.13 Interface/protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4. Installation, connection and commissioning ............................ 13
4.1 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2 Wiring diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5. Operating the device ..................................................................... 16
5.1 Display elements in use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2 Menu overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.3 "AL" menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.3.1 Response value setting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.4 "out" menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.4.1 Configuration of the relay operating mode . . . . . . . . . . . . . . . . . . . . 18
5.4.2 Relay alarm assignment "r1" and "r2" and LED assignment. . . . . . 18
5.4.3 Fault memory configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.4.4 Interface configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.5 "t" menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.5.1 Time configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.6 "SEt" menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.6.1 Function configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.7 Measured value display and history memory. . . . . . . . . . . . . . . . . . . . . . . 19
6. Data access using the BMS protocol ........................................... 20
7. IsoData data string ......................................................................... 21
8. Technical data ................................................................................. 22
8.1 Tabular presentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.2 Standards, approvals and certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
8.3 Ordering details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table of Contents

isoES425_D00214_00_M_XXEN/01.2019
4
Important information
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 in this manual, we
have used symbols to identify important instructions and information. The meaning of
these symbols is explained below:
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 opti-
mum use of the product.
This manual is intended for qualified personnel working in electrical engi-
neering and electronics!
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
1.2.2 Repair service
Repair, calibration, update and replacement service for Bender products
• Repair, calibration, testing and analysis of Bender products
• Hardware and software update for Bender devices
• Delivery of replacement devices for faulty or incorrectly delivered Bender devices
• Extended warranty for Bender devices with in-house repair service or replacement
device at no extra cost
Telephone: [phone]*
Fax: [phone]
In Germany only: 0700BenderHelp (Tel. and Fax)
E-mail: [email protected]
Telephone: [phone]** (technical issues)
[phone]**, -785** (commercial issues)
Fax: [phone]
E-mail: [e-mail]

Important informationImportant information
5
isoES425_D00214_00_M_XXEN/01.2019
1.2.3 Field service
On-site service for all Bender products
• Commissioning, parameter setting, maintenance, troubleshooting for Bender
products
• Analysis of the electrical installation in the building (power quality test, EMC test,
thermography)
• Practical training courses for customers
*Available from 7.00 a.m. to 8.00 p.m. on 365 days of the year (CET/UTC+1)
**Mo-Thu 7.00 a.m. - 8.00 p.m., Fr 7.00 a.m. - 13.00 p.m
1.3 Training courses
Bender is happy to provide training regarding the use of test equipment.
The dates of training courses and workshops can be found on the Internet at www.bend-
er-de.com -> 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 Lieferbedingungen für Erzeugnisse und Leis-
tungen der Elektroindustrie" (software clause in respect of the licensing of standard soft-
ware 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 Ele-
ktrotechnik- und Elektronikindustrie e.V., (German Electrical and Electronic Manufactur-
ers' Association) also applies.
Conditions of sale and delivery can be obtained from Bender in printed or electronic for-
mat.
Telephone: [phone]**, -762** (technical issues)
[phone]** (commercial issues)
Fax: [phone]
E-mail: [e-mail]
Internet: www.bender-de.com
1.5 Inspection, transport and storage
Inspect the dispatch and equipment packaging for damage, and compare the contents
of the package with the delivery documents. In the event of damage in transit, please
contact Bender immediately. The devices must only be stored in areas where it is protect-
ed from dust, humidity and spray or dripping water, and in which the specified storage
temperatures can be assured.
1.6 Warranty and liability
Warranty and liability claims in the event of injury to persons or damage to property are
excluded if they can be attributed 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 manufacturer.
• Non-observance of technical data.
• Repairs carried out incorrectly and the use of replacement parts or accessories not
approved 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 person-
nel working on the device. Furthermore, the rules and regulations that apply for accident
prevention at the place of use must be observed.

isoES425_D00214_00_M_XXEN/01.2019
6
Important information
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 poli-
cies 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 13th August 2005 must be taken back by
the manufacturer and disposed of properly.
For more information on the disposal of Bender devices, refer to our website at
www.bender-de.com -> Service & support.

isoES425_D00214_00_M_XXEN/01.2019 7
Safety instructions
2. Safety instructions
2.1 General safety instructions
Part of the device documentation in addition to this manual is the enclosed "Safety in-
structions for Bender products".
2.2 Work activities on electrical installations
If the device is used outside the Federal Republic of Germany, the applicable local stand-
ards and regulations must be complied with. The 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. The rules for working on electrical systems must be
observed.
2.3 Intended use
The ISOMETER® isoES425 monitors the insulation resistance RFof unearthed AC, AC/DC
and DC systems (IT systems) for energy storage devices up to AC/DC 400 V. DC compo-
nents existing in AC systems do not influence the operating characteristics when a mini-
mum load current of DC 10 mA flows. A separate supply voltage Usallows de-energised
systems to be monitored too. By using the isoES425 in network operation, the connection
to earth is monitored for interruptions, which are indicated as faults. When operated as
an island network, the isoES425 takes over the monitoring of the island network (IT sys-
tem).
In order to meet the requirements of applicable standards, customised parameter set-
tings must be made on the equipment in order to adapt it to local equipment and oper-
ating conditions. Please heed the limits of the area of application indicated in the
technical specifications.
Any other use than that described in this manual is regarded as improper.
.
Only qualified personnel are permitted to carry out the work necessary to in-
stall, commission and run a device or system.
To ensure that the ISOMETER® functions correctly, an internal resistance of
≤ 1 kΩ must exist between L1/+ and L2/- via the source (e.g. the transformer)
or the load.
In case the ISOMETER® issues an alarm message, the insulation fault should
be eliminated as quickly as possible.
The alarm message of the ISOMETER® must be audible and/or visible even
when the device is installed inside a control cabinet.

isoES425_D00214_00_M_XXEN/01.2019
8
Function
3. Function
3.1 Device features
• Monitoring the insulation resistance RFfor unearthed AC, DC systems
• Measuring the nominal system voltage Un(True RMS) with undervoltage/overvolt-
age detection
• Measuring the offset voltages system to earth (L1+/PE and L2-/PE)
• Automatic adaptation to the system leakage capacitance Ceup to 100 F
• Selectable start-up delay, response delay and delay on release
• Two separately adjustable response value ranges of 1…990 k
(Alarm 1, Alarm 2)
• Alarms are indicated via LEDs ("AL1", "AL2"), a display and alarm relays ("K1", "K2")
• Automatic device self test with connection monitoring
• N/C or N/O operation selectable
• Measured value indication via multi-functional LCD
• Fault memory can be activated
• RS-485 (galvanically isolated) including the following protocols:
• BMS interface (Bender measuring device interface) for data exchange with other
Bender components
• IsoData (for continuous data output)
• Password protection to prevent unauthorised parameter changes
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 r.m.s. value
of the nominal system voltage Unbetween L1/+ and L2/-, as well as the offset voltages
UL1e (between L1/+ and earth) and UL2e (between L2/- and earth) are also measured.
In the DC system, from a minimum nominal system voltage, the ISOMETER® determines
the faulty conductor L1/+/L2/-, i.e. the distribution of the insulation resistance RFbe-
tween conductors L1/+ and L2/- and indicates this by means of a positive or negative sign
preceding the insulation resistance measured value. The value range of the faulty con-
ductor is +/-100 %:
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%)
In the AC system, the location of the fault in the DC link is indicated by a positive or neg-
ative sign preceding the insulation resistance measured value in the AC system from a
minimum nominal system voltage between the AC system and earth, caused by a fault in
a connected DC circuit. A percentage distribution to the location of the fault is not possi-
ble. The faulty conductor "R%" is only represented as a one-sided fault on L1/+ (+100 %)
or L2/- (-100 %).
Also from a minimum nominal system voltage, the ISOMETER® determines the insulation
resistance RUGF from the offset 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 RFand Cerelation that varies considerably.
It is possible to assign the detected fault or the faulty conductor to an alarm relay via the
menu. If the values RFor Unexceed 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 operating mode of the relay (n.c./n.o.) can be set
and the fault memory "M" can be activated in this menu.
If the values RFor Undo not violate their respective 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" will go out. If the fault memory is ac-
tivated, the alarm relays remain in alarm state and the LEDs stay lit 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 as well as the control buttons on the front panel; this function can
be password-protected. Parameterisation is also possible via the BMS bus, e.g. by using
the BMS Ethernet gateway (COM465IP).
Display Meaning
-100 % One-sided fault on conductor L2/-
0 % Symmetrical fault
+100 % One-sided fault on conductor L1/+

FunctionFunction
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isoES425_D00214_00_M_XXEN/01.2019
3.2.1 Monitoring of the insulation resistance
The two parameters "R1" and "R2", which monitor the insulation resistance RF, can be
found in the response value menu "AL" (see table on Page 16). The value R1 can only be
set higher than the value R2. If the insulation resistance RFreaches or falls below the val-
ues R1 or R2, this leads to an alarm message. If RFexceeds the values R1 or R2 plus the hys-
teresis value (see table on Page 16), the alarm is be cleared.
3.2.2 Undervoltage/overvoltage monitoring
In the response value menu "AL" (refer to Page 16), the two parameters ("U <" and "U >")
for monitoring the nominal system voltage Uncan be activated or deactivated. The max-
imum undervoltage value is limited by the overvoltage value.
The R.M.S. value of the nominal system voltage Unis monitored. If the nominal system
voltage Unreaches, falls below or exceeds the limit values ("U <" or "U >"), an alarm will
be signalled. If the maximum permissible nominal system voltage Unset for the
ISOMETER® is exceeded, an alarm will be triggered even if the overvoltage limit value has
been deactivated. The alarm will be deleted when the threshold values plus hysteresis
(refer to Page 16) are no longer violated.
3.2.3 Self test/error codes
The integrated self test function checks the function of the insulation monitoring device
and the connection to earth. The alarm relays are not switched during an automatically
started self test. For a manually started self test, the switching of the alarm relays can be
set via the parameter "test" in the alarm assignment ("out" menu, Page 17). During the
test, the display indicates "tES".
When malfunctions are detected or connections are missing, the LEDs "ON"/"AL1"/"AL2"
flash. The respective error codes ("E.xx") are indicated on the display and when factory
settings has been selected, relay "K2" switches.
The relays can be assigned to a device error with the parameter "Err" in the "out" menu in
the alarm assignment.
Error codes
If, contrary to expectations, a device error should occur, error codes will appear on the
display. Some of these are described below:
Internal device errors "E.xx" can be caused by external disturbances or internal hardware
errors. If the error message occurs again after restarting the device or after a reset to fac-
tory settings (menu item "FAC") , the device must be repaired.
After eliminating the fault, 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.
Error code Meaning
E.01
PE connection fault
The connections of "E" or "KE" to earth are interrupted.
Action:
Check connection, eliminate error. The error code will be erased auto-
matically once the error has been eliminated.
E.02
System connection fault
The internal resistance of the system is too high, the connection "L1/+"
or "L2/-" to the system is interrupted or the DC system being monitored
has the wrong polarity at Un> 50 V.
Action:
Check connection, eliminate error. The error code will be erased auto-
matically once the error has been eliminated.
E.05 Measurement technique error/calibration invalid
for the current software version
E.07
The maximum permissible system leakage capacitance Ceaccord-
ing to the technical data sheet 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.

FunctionFunction
10 isoES425_D00214_00_M_XXEN/01.2019
Automatic self test
The device runs a self test after connecting the supply voltage Usand afterwards every 24
hours (selectable at “"t" menu” auf Seite 18 : off, 1h, 24 h).
Manual self test
A self test is initiated by pressing the test button for more than 1.5 s. While pressing the
internal test button "T", all display elements available for this device are shown.
3.2.4 Connection monitoring
The connection monitoring activated by the self test checks the connections of the ter-
minals "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 dis-
play.
The system connection monitoring is used to check the connections of terminals "L1/+"
and "L2/-" to the system to be monitored. When an interruption or a high-resistance con-
nection 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 discon-
nected using the parameter "nEt" in the "SEt" menu.
3.2.5 Malfunction
In addition to the described self test, several functions in the insulation monitoring de-
vice are continuously checked during operation. If a fault is detected, the device error
(Err) will be signalled. The error code E.xx appears on the display as an identifier for the
error type xx and the LEDs "ON"/"AL1"/"AL2" flash.
If the error occurs again after restarting the device or after restoring the factory settings,
please contact Bender service.
3.2.6 Alarm assignment of the alarm relays "K1"/"K2"
The messages "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 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 value to "S.AL = on", the ISOMETER® starts
with the insulation measured value RF= 0  and sets all activated alarms. The alarms will
only be cleared when the measured values are up-to-date and no thresholds are exceed-
ed. When set to "S.AL = off" (factory setting), the ISOMETER® starts without an alarm. It is
recommended that the "S.AL" parameter value is set identically for both relays.
3.2.7 Measuring and response times
The measuring time is the period essential for the detection of the measuring value. The
measuring time is reflected in the operating time tae . For the insulation resistance meas-
ured value, it is mainly determined by the necessary measuring pulse duration, which de-
pends on the insulation resistance RFand the system leakage capacitance Ceof the
system to be monitored. The measuring pulse is produced by the measuring pulse gen-
erator 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 nominal system voltage measurement Unis independent and consider-
ably 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 insulation
resistance measured 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 alarm assignment hast 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 measuring value
is violated for the period of ton without interruption. Every time the threshold value is vi-
olated 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 specified in the alarm assignment has 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 toff without
interruption. Each time the threshold value is not violated for the period toff, the delay on
release "toff" restarts once again.

FunctionFunction
11
isoES425_D00214_00_M_XXEN/01.2019
Start-up delay t
After connection to the supply voltage Usthe alarm indication for the preset time (0…10
s) in the parameter "t" is suppressed.
3.2.8 Password protection (on, OFF)
If password protection has been activated (on), settings can only be made after the cor-
rect password has been entered (0...999).
3.2.9 Factory settings FAC
Activating the factory settings will reset all modified settings, except interface parame-
ters, to the default upon delivery.
3.2.10 External, combined test or reset button T/R
Reset = Press the external button < 1.5 s
Reset with subsequent test= Press the external button > 1.5 s
Stop mode = Press and hold the external button
Stop mode 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. Galvanic paral-
lel connection of several test or reset inputs for combined testing of insulation monitor-
ing devices is not permitted.
3.2.11 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/external)
or the supply voltage Usis turned off.
3.2.12 History memory HiS
When the first fault occurs after clearing the history memory, all measured values (that
are marked in the table on Page 18) are saved in the history memory. This data can be
read out using the "HiS" menu item. In order to be able to record a new data record, the
history memory must first be cleared via the menu using "Clr".
3.2.13 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). ASCII characters are used for data transfer.
• IsoData
The ISOMETER® continuously sends an ASCII data string with a cycle of approximately 1 s.
Communication with the ISOMETER® in this mode is not possible and no additional send-
er may be connected via the RS-485 bus cable. The ASCII data string for the ISOMETER® is
described on Page 20.
The parameter address, baud rate and parity for the interface protocols are configured in
the "out" menu.
The IsoData protocol is activated by setting "Adr = 0".
With a valid bus address (i.e. not equal to 0), the BMS protocol is activated.
In this case, the baud rate for the BMS protocol is set to
9,600 baud.

isoES425_D00214_00_M_XXEN/01.2019
12
Installation, connection and commissioning
4. Installation, connection and commissioning
4.1 Mounting
• DIN rail mounting:
Snap the rear mounting clip of the device into place in such a way that a safe and
tight fit is ensured.
• Screw mounting:
Use a tool to position the rear mounting clips so that they project beyond the enclo-
sure (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 installa-
tion has been de-energised. The rules for working on electrical systems
must be observed.
If the ISOMETER® is used in rail vehicles, it must be ensured that the
ISOMETER® is installed within a control cabinet that complies with the fire
protection requirements of DIN EN 45545-2.
Dimension diagram, sketch for screw mounting and push-wire terminal connection:
All dimensions in mm
The front plate cover can be opened at the lower part marked with an arrow.
4.2 Wiring diagram
Terminals "A1" and "A2" are to be connected to the supply voltage Usaccording to IEC
60364-4-43, i.e. the connections are to be protected against short circuit by means of a
protective device (a 6 A fuse is recommended).
Devices for protection against short circuit in conformity with IEC 60364-4-43 for the cou-
pling of terminals "L1/+" and "L2/-" to the IT system to be monitored can be omitted if the
wiring is carried out in such a manner as to reduce the risk of a short circuit to a minimum.
Only one ISOMETER® may be controlled via a test/reset button. It is not allowed to use a
parallel connection of several test or reset inputs for combined testing of ISOMETER®s.
93
45
67,5
36
31,1
47,5
74,5
2
2
2
1
3
107
Zubehör
Klick
M4
100

isoES425_D00214_00_M_XXEN/01.2019 13
Fig. 4.1: Wiring diagram of the isoES425
For details about the conductor cross sections required for wiring, refer to the technical data from Page 21.
U
S
L1/+
KE A1 A2
Test / Reset
14 24 11
K1 K2
T/R
L2/
L1/+
L2/-
PE
L3
ON
TR
MENU
AL1 AL2
k
<
k
ISOMETER
isoES425
L1/+ L2/-
EKEA1A2
14 24 11
T/R AB
COM465IP
RS-485
AB
R
R
on
o
E

Installation, connection and commissioningInstallation, connection and commissioning
14 isoES425_D00214_00_M_XXEN/01.2019
Wiring diagram legend:
Terminal Connections
A1, A2 Connection to the supply voltage Usvia fuse (line protection):
If being supplied from an IT system, both lines have to be protected by a fuse.*
E, KE Connect each terminal separately to PE:
The same wire cross section as for "A1", "A2" is to be used.
L1/+, L2/– Connection to the AC or DC system to be monitored
T/R Connection for the 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 connectable terminating resistor
Example: Connection of a BMS Ethernet gateway COM465IP
* For UL applications:
Use 60/75 °C copper lines only!
For UL and CSA applications, the supply voltage Usmust be protected via
5 A fuses.
Connect the device according to the wiring diagram.
4.3 Commissioning
1. Check that the ISOMETER® is properly connected to the system to be monitored.
2. Connect the supply voltage Usto the ISOMETER®.
The device carries out a calibration, a self test and adjusts itself to the IT system to be
monitored. When high system leakage capacitances are involved, this procedure
may take up to 4 min. The standard display then appears showing the present insu-
lation resistance RF, e.g.:
The pulse symbol signals an error-free update of the resistance measured value. If
the measuring value cannot be updated due to disturbances, the pulse symbol will
be blanked.
3. Start a manual self test by pressing the test button "T". Whilst the test button is
pressed and held down, 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 (refer to Page 9). 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 the factory settings for suitability.
Are the settings suitable for the installation to be monitored?
The list of factory settings are shown in the tables from Page 16.
5. Check the function using a genuine insulation fault.
Check the ISOMETER® in the system being monitored against earth, e.g. via a suita-
ble resistance.

isoES425_D00214_00_M_XXEN/01.2019 15
Operating the device
5. Operating the device
The menu structure is illustrated schematically on the following pages.
After pressing the "MENU" button for > 1.5 s, the first menu item "AL" appears. Use
and (Enter) buttons for navigation and settings.
Up and down button:
- Navigate up or down in the menu settings
- Increase or decrease values
MENU
Pressing the MENU/Enter button for more than 1.5 s:
- Start menu mode
or
- When the device already is in menu mode:
Exit menu item (Esc). Any recent
changes won't be stored.
Pressing the MENU/Enter button for less than 1.5 s:
- Confirm menu selection
or
- Confirm modified value
The areas of the display that can be configured flash!
5.1 Display elements in use
Device front/display Function
ON
AL1
AL2
green - on
yellow - alarm
yellow - alarm
T
Up button
Test button (press > 1.5 s)
By pressing and holding the test button, the display
elements are indicated
R
Down button
Reset button (press > 1.5 s)
MENU
ENTER
MENU button (press > 1.5 s)
1
U: Nominal system voltage Un
R: Insulation resistance RF
C: System leakage capacitance Ce
2Monitored conductor
3
= : Voltage type DC
~ : Voltage type AC
4Measured values and units
5Password protection is activated.
6In the menu mode, the operating mode of the respec-
tive alarm relay is displayed.
7Communication interface
sends in IsoData mode.
8The fault memory is activated.
9Condition symbols
10 Identification for response values and response value
violation
ON AL1 AL2
T MENU R
+
test onoff MAdr
L1L2 C
<
>
s
kM %
Fµ
{
{
{
{
12 3
4
567
8
{
9
{
10
: Error-free measured value update
Assignment according to
table on Page 17

Operating the deviceOperating the device
16 isoES425_D00214_00_M_XXEN/01.2019
5.2 Menu overview
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
Enter
or
t > 5 min.
k
R
R [kΩ]
C [μF]
U L1 L2 [ V]
UL1 [ V]
UL2 [ V]
R [ %]
U R [kΩ]
Standard display
Measurement display
Menu
Esc
Menu selection
AL
out
t
SEt
InF
HiS
ESC
Enter
Esc
Parameter selection
P1
. . .
Pn
ESC
Optional Passwort
Edit parameters
Save parameters
Enter
Enter
Enter
Esc
Funktion Button Confirm
Enter
Menu
Esc
Test
Reset
Select, acknowledge input
Call menu
Exit menu item
Start device test
Clear fault memory
/ MENU Short
> 1.5 s
> 1.5 s
> 1.5 s
> 1.5 s
/ MENU
/ MENU
/ T
/ R
5.3 "AL" menu
5.3.1 Response value setting
The two parameters that monitor the insulation resistance RF, "R1" and "R2", can be found
in the response value menu "AL". The value R1 can only be set higher than the value R2.
If the insulation resistance RFreaches or falls below the values R1 or R2, this leads to an
alarm message. If RFexceeds the values R1 or R2 plus the hysteresis value (see table be-
low), the alarm will be cleared.
The two parameters ("U <" and "U >") for monitoring the nominal system voltage Uncan
also be activated or deactivated in the response value menu "AL". The maximum under-
voltage value is limited by the overvoltage value.
FAC = Factory settings; Cs = Customer settings
Display Activation Setting value Description
FAC Cs Range FAC Cs
R1 < R2 … 990 69 k Pre-alarm value Ran1
Hys. = 25 %/min. 1 k
R2 < 1… R1 23 k Alarm value Ran2
Hys. = 25 %/min. 1 k
U < off 10 … U> 30 V
Alarm value
undervoltage RMS
Hys. = 5 %/min. 5 V
U > off U< … 500 500 V
Alarm value
overvoltage RMS
Hys. = 5 %/min. 5 V

Operating the deviceOperating the device
17
isoES425_D00214_00_M_XXEN/01.2019
5.4 "out" menu
5.4.1 Configuration of the relay operating mode
FAC = Factory settings; Cs = Customer settings
5.4.2 Relay alarm assignment "r1" and "r2" and LED assignment
In the alarm assignment, each alarm is assigned to the corresponding relay with the set-
ting "on". The LED indication is directly assigned to the alarms and is not related to the
relays.
If the device can assign an asymmetrical insulation fault to the corresponding conductor
(L1/+ or L2/-), it will only signal the respective alarm.
FAC = Factory settings; Cs = Customer settings
: LED off : LED flashes : LED on
Relay K1 Relay K2 Description
Display FAC Cs Display FAC Cs
n.c. n.c. Operating mode of the relay n.c./n.o.
K1 „r1“ K2 „r2“ LEDs Alarm
description
Display FAC Cs Display FAC Cs ON AL1 AL2
off on    Device error E.xx
r1
+R1 <  on r2 +R1 <  off   
Pre-alarm R1
Fault RFat L1/+
r1
-R1 <  on r2 -R1 <  off   
Pre-alarm R1
Fault RF at L2/-
r1
+R2 <  off r2
+R2 <  on Alarm R2
Fault RFat L1/+
r1
-R2 <  off r2
-R2 <  on Alarm R2
Fault RF at L2/-
r1
U < V off r2
U < V on Alarm Un
undervoltage
r1
U > V off r2
U > V on   
Alarm Un
Overvoltage
r1
test off r2 test off   
Manually
started
device test
r1
S.AL on r2 S.AL on    Device start with alarm
1
2
1
Err
2
Err
5.4.3 Fault memory configuration
FAC = Factory settings; Cs = Customer settings
5.4.4 Interface configuration
FAC = Factory settings; Cs = Customer settings;
( ) = User setting that is not modified by FAC.
Display FAC Cs Description
Moff Memory function for alarm messages (fault memory)
Display Setting value Description
Range FAC Cs
Adr 0 / 3 … 90 3( ) Bus addr.
Adr = 0 deactivates BMS and activates
the isoData data logger with continu-
ous data output (115k2, 8E1)

Operating the deviceOperating the device
18 isoES425_D00214_00_M_XXEN/01.2019
5.5 "t" menu
5.5.1 Time configuration
FAC = Factory settings; Cs = Customer settings
5.6 "SEt" menu
5.6.1 Function configuration
FAC = Factory settings; Cs = Customer settings
Display Setting value Description
Range FAC Cs
t0 … 10 0 sStart-up delay during device start
ton 0 … 99 0 sResponse delay K1 and K2
toff 0 … 99 0 sDelay on release K1 and K2
test OFF / 1 / 24 24 hRepetition time device test
Display Activation Setting value Description
FAC Cs Range FAC Cs
off 0 . . . 999 0Password for parameter setting
nEt on Test of the system connection dur-
ing device test
S.Ct on Device test during device start
FAC Restore factory settings
SYS For Bender service only
5.7 Measured value display and history memory
RFis continuously indicated on the display (standard display). All other measured value
displays switch to the standard display after a maximum of 5 min. The pulse symbol indi-
cates a current measured value. If this symbol does not appear, the measurement is still
running and the latest valid measured value will be displayed. The symbols "<" or ">"will
be displayed additionally to the measured value when a response value has been
reached or violated, or the measured value is below or exceeds the measuring range.
: The measured value is indicated in the history memory.
HiS Display Description
±R k Insulation resistance RF
1 k ... 4 M Resolution 1 k
C F
System leakage capacitance Ce
0 F ... 105 F Resolution 1 F
No update when RFis < 10 k.
~ ± U L1 L2 = V Nominal system voltage L1 - L2 Un
0 VRMS … 500 VRMS Resolution 1 VRMS
±U L1 = V
Residual voltage L1/+ - PE UL1e
0 VDC … ±500 VDC Resolution 1 VDC
±U L2 = V
Residual voltage L2/- - PE UL2e
0 VDC … ±500 VDC Resolution 1 VDC
±R % Fault location in %
-100 % …+100 %
U R = k
Insulation resistance RUGF
1 k … 4 M Resolution 1 k
RUGF is an approximate value for asymmetrical insula-
tion faults and can be used as a trend indicator with
short measuring times.

isoES425_D00214_00_M_XXEN/01.2019 19
Data access using the BMS protocol
6. Data access using the BMS protocol
The BMS protocol is an essential component of the Bender measuring device interface
(BMS bus protocol). ASCII characters are used for the data transfer.
BMS channel no. Operation value Alarm
1RFPre-alarm R1
2RFAlarm R2
3Ce----
4UnUndervoltage
5UnOvervoltage
6 --- Connection fault earth (E.01)
7 --- Connection fault system (E.02)
8 --- All other device faults (E.xx)
9 Fault location [%] ---
10 UL1e ---
11 UL2e ---
12 Update counter ---
13 RUGF ---
14 --- ---
15 --- ---

isoES425_D00214_00_M_XXEN/01.2019
20
IsoData data string
7. IsoData data string
In IsoData mode, the ISOMETER® continuously sends the whole data string with a cycle
time of approximately 1 s. Communication with the ISOMETER® in this mode is not possi-
ble and no additional sender may be connected via the RS-485 bus cable.
IsoData is activated in the "out" menu, menu item "Adr" when it has been set to Adr = 0.
In this case, the symbol "Adr" flashes on the measured value display.
String Description
!; Start sign
v; Insulation fault location ' ' / '+' / '-'
1234, 5; Insulation resistance RF[k]
1234; System leakage capacitance Ce[µF]
1234, 5; reserved
+1234; Nominal system voltage Un[VRMS]
Nominal system voltage type: AC or unknown: ' ' DC: '+'/'-'
+1234; Offset voltage UL1e [VDC]
+1234; Offset voltage UL2e [VDC]
+123; Insulation fault location -100 … +100 [%]
1234, 5; Approximate asymmetrical insulation resistance RUGF [k]
1234;
Alarm message [hexadecimal] (without leading "0x")
The alarms are included in this value with the OR function.
Assignment of the alarms:
0x0002 Device error
0x0004 Prewarning insulation resistance RFat L1/+
0x0008 Prewarning insulation resistance RFat L2/-
0x000C Prewarning insulation resistance RFsymmetrical
0x0010 Alarm insulation resistance RFat L1/+
0x0020 Alarm insulation resistance RFat L2/-
0x0030 Alarm insulation resistance RFsymmetrical
0x0040 Reserved
0x0080 Reserved
0x0100 Alarm undervoltage Un
0x0200 Alarm overvoltage Un
0x0400 Message system test
0x0800 Device start with alarm
1Update counter, counts consecutively from 0 to 9.
It increases with the update of the insulation resistance value.
<CR><LF> String end