Bender ISOMETER isoPV1685RTU User manual

isoPV1685xxx_D00007_08_M_XXEN/03.2023
ISOMETER®
isoPV1685RTU / isoPV1686P
Insulation monitoring device for unearthed
photovoltaic systems
isoPV1685RTU: software version D0532 V3.0x
isoPV1685P: software version D0525 V2.0x
From serial number 2108…
Manual EN

Bender GmbH & Co. KG
Londorfer Str. 65 • 35305 Grünberg • Deutschland
Postbox 1161 • 35301 Grünberg • Deutschland
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.
Fotos: Bender archive

Table of Contents
3
isoPV1685xxx_D00007_08_M_XXEN/03.2023
Table of Contents
1. Important information ............................................................................................ 7
1.1 How to use this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
1.2 Technical support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.2.1 End customer support and advice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.2.2 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.2.3 Customer service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.3 Training courses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.4 Delivery conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.5 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.6 Warranty and liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.7 Disposal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2. Safety instructions .................................................................................................. 11
2.1 General safety instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2.2 Work activities on electrical installations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2.3 Device-specific safety instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
2.4 Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3. Function .................................................................................................................... 13
3.1 Features isoPV1685RTU and isoPV1685P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.2 Product description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.3 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.3.1 General functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.3.2 µSD card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.3.3 Insulation monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.3.4 Insulation fault location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.3.5 Assignment of the alarm relays K1, K2, K3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3.3.6 Measured value transmission to the control inputs of the inverter . . . . . . . . . .16
3.3.7 History memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3.4 Self test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.4.1 Self test after connection to the supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.4.2 Automatic self test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.4.3 Manual self test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
4. Device overview ...................................................................................................... 19
4.1 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
4.2 Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.3 Display and operating controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.3.1 Display elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.3.2 Operating elements in the service lid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
4.3.3 Access to DIP switch and to the µSD card via the service lid . . . . . . . . . . . . . . . .22

Table of Contents
4isoPV1685xxx_D00007_08_M_XXEN/03.2023
5. Mounting and connection .................................................................................... 23
5.1 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.2 Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.2.1 Connection requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.2.2 Wiring diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
5.2.3 Connecting the EDS to the ISOMETER® isoxx1685DP . . . . . . . . . . . . . . . . . . . . . . .27
6. Commissioning ....................................................................................................... 28
6.1 Commissioning flow chart insulation fault monitoring . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.2 Commissioning flow chart insulation fault location (isoPV1685P only) . . . . . . . . . . .29
7. Settings ..................................................................................................................... 30
7.1 Setting BMS address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
7.2 Setting an alarm for insulation faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
7.3 Setting the system leakage capacitance or measurement speed . . . . . . . . . . . . . . . .31
7.4 Parameter setting of the insulation fault location
(isoPV1685P only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
7.5 Resetting alarm messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
7.6 Parameter setting with the iso1685 set tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
8. Device communication .......................................................................................... 34
8.1 RS-485 interface with BMS protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
8.1.1 Topology RS-485 network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
8.1.2 BMS protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
8.1.3 BMS master . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
8.1.4 Commissioning of an RS-485 network with BMS protocol . . . . . . . . . . . . . . . . . .36
8.1.5 Address setting and termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
8.1.6 Setting the BMS address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
8.1.7 Alarm and operating messages via BMS bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
8.1.8 Performing a firmware update via the BMS bus . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
8.2 CAN bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
8.3 Error codes BMS and CAN bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
8.4 RS-485 interface with Modbus protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
9. Diagrams ..................................................................................................................41
9.1 The leakage capacitance depends on the ins. resistance . . . . . . . . . . . . . . . . . . . . . . . .41
9.2 Response time for insulation measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
9.3 Example of alarms stored in the history memory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
10. Technical Data ....................................................................................................... 43
10.1 Factory settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
10.2 Tabular data isoPV1685... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
10.3 Standards, approvals and certifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
10.4 Ordering details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
10.5 Change log. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

Table of Contents
5isoPV1685xxx_D00007_08_M_XXEN/03.2023

Important information
7
isoPV1685xxx_D00007_08_M_XXEN/03.2023
1. Important information
1.1 How to use this manual
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.
This manual is intended for qualified personnel working in electrical
engineering and electronics!
Read the manual before you begin to mount, connect, and
commission the unit. Always keep the manual within easy reach for
future reference following commissioning.
DANGER
This signal word indicates that there is a high risk of danger that will
result in electrocution 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
8isoPV1685xxx_D00007_08_M_XXEN/03.2023
1.2 Technical support
1.2.1 End customer support and advice
Technical support by phone or e-mail for all Bender products
• Questions concerning specific customer applications
• Commissioning
• Troubleshooting
Telephone: [phone] (365 days from 07:00 - 20:00 Uhr [MEZ/UTC +1])
Fax: [phone]
0700BenderHelp (Tel. and Fax in Germany only)
E-mail: [email protected]
1.2.2 Repair
Repair, calibration, update and replacement service for Bender products
• Repairing, calibrating, testing and analysing Bender products
• Hardware and software update for Bender devices
• Delivery of replacement devices
• Extended guarantee, in-house repair service, replacement devices at no extra cost
Telephone: [phone]* (technical issues)
[phone]*, -785* (sales)
Fax: [phone]
E-mail: [email protected]
Please send the devices for repair to the following address:
Bender GmbH, Repair-Service,
Londorfer Strasse 65,
35305 Grünberg
1.2.3 Customer service
On-site service for all Bender products
• Commissioning, parameter setting, maintenance, troubleshooting
• Analysis of the electrical installation in the building (power quality test, EMC test,
thermography)
• Training courses for customers
Telephone: [phone]*, -762* (technical issues)/
[phone]* (sales)
Fax: [phone]
E-mail: [e-mail]
Internet: www.bender.de
* Mo-Thu 07:00 a.m. - 16:00 p.m. , Fr 07:00 a.m. - 13:00 p.m.

Important information
9
isoPV1685xxx_D00007_08_M_XXEN/03.2023
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.bender.de -> Know-how -> Seminars.
1.4 Delivery conditions
Bender sale and delivery conditions apply.
For software products, the "Softwareklausel zur Überlassung von Standard-Software als Teil
von Lieferungen, Ergänzung und Änderung der Allgemeinen Lieferbedingungen für Er-
zeugnisse 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 (Zentral-
verband Elektrotechnik- und Elektronikindustrie e.V.) (German Electrical and Electronic Ma-
nufacturers' Association) also applies. Amending the “General Conditions for the supply of
Products and Services of the Electrical and Electronics Industry” (GL)*
Sale and delivery conditions can be obtained from Bender in printed or electronic format.
1.5 Storage
The devices must only be stored in areas where they are protected from dust, damp, and
spray and dripping water, and in which the specified storage temperatures can be ensured.
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.

Important information
10 isoPV1685xxx_D00007_08_M_XXEN/03.2023
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 direc-
tive on the restriction of certain hazardous substances in electrical and electronic equip-
ment (RoHS directive) apply in the European Community. In Germany, these policies are
implemented through the "Electrical and Electronic Equipment Act" (ElektroG). According
to this, the following applies:
• Electrical and electronic equipment are not part of household waste.
• Batteries and accumulators are not part of household waste and 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 must 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 -> Service & Support.

Safety instructions
11
isoPV1685xxx_D00007_08_M_XXEN/03.2023
2. Safety instructions
2.1 General safety instructions
Part of the device documentation in addition to this manual is the enclosed "Safety instruc-
tions for Bender products".
2.2 Work activities on electrical installations.
If the device is used outside the Federal Republic of Germany, the applicable local stan-
dards and regulations must be complied with. The European standard EN 50110 can be
used as a guide.
Read the operating manual before starting to mount, connect and
com-mission the device. After successful commissioning, keep the
manual within easy reach for future reference.
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.

Safety instructions
12 isoPV1685xxx_D00007_08_M_XXEN/03.2023
2.3 Device-specific safety instructions
2.4 Intended use
The isoPV1685RTU and the isoPV1685P are used for insulation monitoring of large photo-
voltaic systems up to AC 1000V and DC 1500 V designed as IT systems. The measurement
method specially developed for slow voltage fluctuations (MPP tracking) monitors the in-
sulation resistance even in systems equipped with large solar generator panels where ext-
remely high system leakage capacitances against earth exist due to interference suppres-
sion methods. Adaptation to system-related high leakage capacitances also occurs auto-
matically.
The isoPV1685P generates locating current pulses required for insulation fault location.
That allows the localisation of the insulation fault using permanently installed or mobile in-
sulation fault locators.
Intended use also implies:
• The observation of all information in the operating manual
• Compliance with test intervals
In order to meet the requirements of applicable standards, the equipment must be adjus-
ted to local equipment and operating conditions by means of customised parameter set-
tings. Please heed the limits of the range of application indicated in the technical data.
Any other use than that described in this manual is regarded as improper.
Installation inside a control cabinet
If the ISOMETER® is installed inside a control cabinet, the insulation fault
message must be audible and/or visible to attract attention.
IT systems with several ISOMETER®s
Make sure that only one active ISOMETER® is connected in each
interconnected system. If IT systems are interconnected via coupling
switches, make sure that ISOMETER®s not currently used are disconnec-
ted from the IT system and deactivated. For IT systems coupled via diodes
or capacitances a central control of the different ISOMETER®s is required.
Prevent measurement errors!
When a monitored IT system contains galvanically coupled DC circuits,
an insulation fault can only be detected correctly if the rectifier valves
(e.g. rectifier diode, thyristors, IGBTs, frequency inverters, …) carry a
minimum current of > 10 mA.
Unspecified frequency range
When connecting to an IT system with frequency components below the
specified frequency range, the response times and response values may
differ from the indicated technical data. However, depending on the
application and the selected measurement method, continuous
insulation monitoring is also possible in this frequency range.

Function
13
isoPV1685xxx_D00007_08_M_XXEN/03.2023
3. Function
3.1 Features isoPV1685RTU and isoPV1685P
• Insulation monitoring of large-scale photovoltaic systems
• Measurement of low-resistance insulation faults
• Separately adjustable response values Ran1 (alarm 1) and Ran2 (alarm 2) (both
200 Ω…1 MΩ) for prewarning and alarm. Ran1 ≥ Ran2 applies.
• Automatic adjustment to high system leakage capacitances up to 2000 µF,
selectable range
• Connection monitoring of L+, L- for reverse polarity (DC only)
• Integrated locating current injector up to 50 mA (isoPV1685P only)
• Device self test with automatic message in the event of a fault
• Alarm relays separately adjustable for insulation fault 1, insulation fault 2 and device
error
• CAN interface to output measured values, statuses and alarms
• RS-485 interface
– isoPV1685P: BMS bus, e.g. to control the insulation fault location
– isoPV1685RTU: BMS bus or Modbus (can be switched using the DIP switch)
• µSD card with data logger and history memory for alarms
Tabular overview of features
* The µSD card is not equipped, but can be inserted later.
The device version isoPV1685P provides a locating current injector.
isoPV1685RTU isoPV1685P
Insulation fault localisation
(locating current injector) X
Digital inputs X X
µSD card * X
CAN bus X X
BMS bus X X
Modbus RTU X
The isoPV1685RTU uses the RS-485 interface for the BMS bus or for
Modbus RTU: The device can be switched between BMS and Modbus.

Function
14 isoPV1685xxx_D00007_08_M_XXEN/03.2023
3.2 Product description
The ISOMETER® isoPV1685RTU is an insulation monitoring device for IT systems in ac-
cordance with IEC 61557-8. The ISOMETER® isoPV1685P is an insulation monitoring device
for IT systems in accordance with IEC 61557-8 and IEC 61557-9.
The ISOMETER®s can be used in photovoltaic installations.
3.3 Functional description
3.3.1 General functional description
Insulation monitoring is carried out using an active measuring pulse which is superimpo-
sed onto the PV system to earth via the integrated coupling.
isoPV1685RTU:
If the insulation resistance between the PV system and earth falls below the preset prewar-
ning response value Ran1, the "Alarm 1" LED lights and the alarm relay K1 switches. If the va-
lue also falls below response value Ran2, the "Alarm 2" LED also lights and the alarm relay K2
switches.
isoPV1685P:
If the insulation resistance between the PV system and earth falls below the preset prewar-
ning response value Ran1, the "Alarm 1" LED lights and the alarm relay K1 switches. If the va-
lue also falls below response value Ran2, the "Alarm 2" LED also lights and the alarm relay K2
switches.
The locating current injector integrated in the device for insulation fault location is either
activated externally via the BMS interface or via the internal backup master function if no
external master has been connected. When starting the insulation fault location, the LED
"PGH on" signals the locating current pulse.
The insulation fault location can be started manually via the digital input 1, e.g. for insula-
tion fault location with mobile insulation fault locators (e.g. EDS195).
3.3.2 µSD card
The integrated µSD card is used as data logger for storing all relevant events.
The following measured values, statuses and alarms are stored during operation:
• Insulation resistance and leakage capacitance
• System voltage, partial voltages to earth, supply voltages
• Temperature locating current injector (isoPV1685P only)
• Temperature coupling L+, L–
• Insulation fault
• Connection faults and device errors

Function
15
isoPV1685xxx_D00007_08_M_XXEN/03.2023
Following each start-up, a new log file is generated. If the current file size exceeds 10 MByte
during operation, a new file is generated. The file name contains the time and date of the
creation time. The typical time that is needed until the maximum file size is reached is ap-
proximately 2 days. Hence, a µSD card with a memory space of 2 GByte can record data for
approx. 400 days.
When the maximum data limit is reached on your card, the oldest file in each case will be
overwritten. The history memory that is also copied to the µSD card contains all alarms in
csv. format.
3.3.3 Insulation monitoring
For insulation monitoring, a pulsating AC measuring voltage is superimposed onto the IT
system. The measuring pulse consists of positive and negative rectangular impulses of the
same amplitude. The period duration depends on the system leakage capacitances in each
case and the insulation resistances of the system to be monitored.
Pulse sequence of the measuring voltage for insulation fault monitoring
An insulation fault between the IT system and earth closes the measuring circuit. If the in-
sulation resistance between system and earth falls below the set response values Ran1 and
Ran2 (response value Ran1 can be set equal or higher than Ran2), the associated alarm relays
K1 (11, 12, 14) or K2 (21, 22, 24) switch. Detected insulation faults are signalled to other bus
devices via the BMS bus. In addition, the alarm LEDs ALARM 1 or ALARM 2 light up.
3.3.4 Insulation fault location
For insulation fault location, a suitable locating current is superimposed onto the faulty IT
system with which insulation fault locators of the EDS... series can locate insulation faults.
The ISOMETER® features an internal locating current injector with IL DC 50 mA.
Pulse sequence of the internal locating current injector for insulation fault location
U
m
t
2 s 4 s 2 s 4 s
I
L
t

Function
16 isoPV1685xxx_D00007_08_M_XXEN/03.2023
When permanently installed insulation fault locators (with master capability) such as the
EDS440 are used, control and synchronisation of the locating current injector is carried out
by one of the insulation fault locators in BMS master mode. For this purpose, the
isoPV1685P has to communicate with the insulation fault locator via the BMS bus.
3.3.5 Assignment of the alarm relays K1, K2, K3
Relay assignment
K1 switches when the value falls below the alarm response value Ran1 (insulation resis-
tance).
K2 switches when the value falls below the alarm response value Ran2 (insulation resis-
tance).
K3 switches in the event of a device error or a connection fault.
3.3.6 Measured value transmission to the control inputs of the inverter
All recorded measured values, operating messages and alarms are made available via the
CAN bus and the BMS bus.
3.3.7 History memory
All warnings, alarms and device errors including "Come", "Go" and "Acknowledgement"
timestamps are stored in the internal history memory.
The history data are copied from the internal EEPROM to the History.csv file on the µSD card
under the following conditions:
• After device start-up
• During operation once per hour
• When a compatible µSD card has been inserted
For the evaluation of the history memory, the Excel tool "iso1685 History.xlsx" can be made
available. This tool allows csv.-file data to be processed and evaluated. By way of example,
history memory entries are shown on page 42.
The tool includes detailed information about the use.
During the insulation fault location process, the function of insulation
resistance measurement is deactivated and the coupling is disconnected
from the mains.

Function
17
isoPV1685xxx_D00007_08_M_XXEN/03.2023
3.4 Self test
3.4.1 Self test after connection to the supply voltage
Once connected to the supply voltage, all internal measurement functions, the compo-
nents of the process control such as data and parameter memory as well as the connections
to earth are checked. Once the self test is finished, after approx. 5 s the normal measure-
ment mode begins.
If a device error or a connection fault is detected, the corresponding alarm will be signalled
via the CAN and the RS-485 interface as well as via the alarm relay K3 (31-32-34). This relay
continuously operates in N/C operation, i.e. it de-energises even in case of a complete de-
vice failure. During this self test, when the device is being started, the alarm relays K1 and
K2 are not switched.
3.4.2 Automatic self test
All supply voltages are continuously monitored.
The following tests are continuously carried out in the background:
• Connection E-KE
•System polarity
• Temperature measurement
• Measuring voltage generator
3.4.3 Manual self test
The self test is started via the CAN or RS-485 interface by a Modbus or BMS master with the
test button or by any CAN bus device.
Only in the manual self test mode (via the CAN or RS-485 interface), the following tests can
be carried out:
• Internal Flash
• Internal RAM
•CPU register
•Watchdogs
•Oscillator
• Function of the Iso measurement technique
• Restart of the device including re-initialising and recalibration (only when the test is
requested via RS-485 interface)
3.4.3.1 Manual self test via the RS-485 interface
During the manual self test via the RS-485 interface, the alarm relays K1 (11-12-14) and K2
(21-22-24) are switched. K3 is only shortly switched after a device restart .

Function
18 isoPV1685xxx_D00007_08_M_XXEN/03.2023
3.4.3.2 Manual self test via CAN bus
isoPV1685RTU and isoPV1685P:
During the insulation fault measurement test, the alarm relay K1 (11-12-14) and the alarm
relay K2 (21-22-24) are switched. K3 won't be switched.
Once a month, carry out a manual self test via the CAN or RS-485
interface to ensure that the device functions correctly!

Device overview
19
isoPV1685xxx_D00007_08_M_XXEN/03.2023
4. Device overview
4.1 Dimensions
All dimensions in mm
ISOMETER
®iso1685
246
125 40,5
40,75
51
368
383
401,5
106
64
8,75
5,2
61,8
76,6
39,8
55,7

Device overview
20 isoPV1685xxx_D00007_08_M_XXEN/03.2023
4.2 Connections
upper graphic
I2+,I2- / I1+, I1- digital Inputs
CAN1 / CAN2 no function
RS485 Term. off / on RS-485 termination
A, B, S RS-485 bus connection (A,B) Protocol: BMS
S= PE potential Connect one end of shield
k, I, kT, IT no function
31, 32, 34 Relay output for internal device errors (LED SERVICE)
21, 22, 24 Relay output for alarm 2 insulation faults
11, 12, 14 Relay output for alarm 1 insulation faults
E / KE Separate connection of E (earth) and KE (reference) to PE.
Connect both to PE
A1, A2 Supply voltage Us DC 24 V Arbitrary polarity
Connection via fuses, 2 A each
lower graphic
L1/+ Connection to L1/+ of the IT system via 1 A fuse
L2/- Connection to L2/- of the IT system via 1 A fuse
I2+ I2- I1+ I1-
I2+ I2- I1+ I1-
CAN 1 CAN 2 RS-485
Term.
o on A B S
A B S
k l kT IT
k I kT IT
31 32 34
K3
31 32 34
21 22 24
K2
21 22 24
11 12 14
K1
11 12 14
E K E
E KE
A1 A2
A1 A2
L2/L-
L2/-
L1/L+
L1/+