Bender ISOMETER iso685

Name: Bender ISOMETER iso685
Brand: Bender
SKU: b7f55478-d74b-405b-a61e-f02baa573544

Insulation monitoring device for unearthed IT AC and DC systems with alarm relays and fault location.

The Bender ISOMETER iso685 is an insulation monitoring device that measures the insulation resistance of unearthed IT AC and DC systems in hospitals, data centres, ships and PV plants. This Modbus TCP template reads insulation resistance, voltages, alarm states and fault location values, and lets you set response values, profile and relays from ModbusCloud.

Protocol: Modbus TCP
Connection: Ethernet, Modbus TCP
Registers: 343, read and write

Brand: Bender
Key readings: Insulation resistance · Minimum insulation resistance · Leakage capacitance · System voltage · System frequency · DC offset · Alarm status · Measurement quality
Available commands: Response value 1 and 2 · Measuring profile · Relay functions · Test and reset · Device on or off
Compatible models: iso685-D · iso685-S · iso685W-D · isoRW685W-D · iso685-D-B · iso685-D-P · isoHR685-D-I-B
Last updated: 20 October 2026

Registers (343)

330 read, 108 write

Name	Unit	Access
Insulation Resistance	Ω	Read
Minimum Insulation Resistance	Ω	Read
System Leakage Capacitance		Read
Voltage L1 L2	V	Read
Voltage L1 L3	V	Read
Voltage L2 L3	V	Read
Voltage L1 PE	V	Read
Voltage L2 PE	V	Read
Voltage L3 PE	V	Read
System Frequency	Hz	Read
Coupling To System		Read
Coupling To Earth		Read
Device Error		Read
Device Inactive		Read
DC Offset	%	Read
Measurement Quality	%	Read
Symmetrical Alarm	%	Read
DC Minus Alarm	%	Read
DC Plus Alarm	%	Read
Measuring Pulse Duration	%	Read
Voltage DC PE	V	Read
Locating Current Positive	A	Read
Locating Current Negative	A	Read
PGH Start Condition		Read
Alarm Status		Read
IO State		Read
Measured Value Counter		Read and write
Channel 1 Number		Read
Channel 1 Insulation Resistance	Ω	Read
Channel 1 Test And Alarm Status		Read
Channel 1 Range And Unit		Read
Channel 2 Number		Read
Channel 2 Insulation Resistance 2	Ω	Read
Channel 2 Test And Alarm Status		Read
Channel 2 Range And Unit		Read
Channel 3 Number		Read
Channel 3 System Leakage Capacitance		Read
Channel 3 Test And Alarm Status		Read
Channel 3 Range And Unit		Read
Channel 4 Number		Read
Channel 4 Voltage L1 L2	V	Read
Channel 4 Test And Alarm Status		Read
Channel 4 Range And Unit		Read
Channel 5 Number		Read
Channel 5 Voltage L1 L3	V	Read
Channel 5 Test And Alarm Status		Read
Channel 5 Range And Unit		Read
Channel 6 Number		Read
Channel 6 Voltage L2 L3	V	Read
Channel 6 Test And Alarm Status		Read
Channel 6 Range And Unit		Read
Channel 7 Number		Read
Channel 7 Voltage L1 PE	V	Read
Channel 7 Test And Alarm Status		Read
Channel 7 Range And Unit		Read
Channel 8 Number		Read
Channel 8 Voltage L2 PE	V	Read
Channel 8 Test And Alarm Status		Read
Channel 8 Range And Unit		Read
Channel 9 Number		Read
Channel 9 Voltage L3 PE	V	Read
Channel 9 Test And Alarm Status		Read
Channel 9 Range And Unit		Read
Channel 10 Number		Read
Channel 10 System Frequency	Hz	Read
Channel 10 Test And Alarm Status		Read
Channel 10 Range And Unit		Read
Channel 11 Number		Read
Channel 11 Coupling To System		Read
Channel 11 Test And Alarm Status		Read
Channel 11 Range And Unit		Read
Channel 12 Number		Read
Channel 12 Coupling To Earth		Read
Channel 12 Test And Alarm Status		Read
Channel 12 Range And Unit		Read
Channel 13 Number		Read
Channel 13 Device Error		Read
Channel 13 Test And Alarm Status		Read
Channel 13 Range And Unit		Read
Channel 14 Number		Read
Channel 14 Device Status		Read
Channel 14 Test And Alarm Status		Read
Channel 14 Range And Unit		Read
Channel 15 Number		Read
Channel 15 DC Offset	%	Read
Channel 15 Test And Alarm Status		Read
Channel 15 Range And Unit		Read
Channel 16 Number		Read
Channel 16 Measurement Quality	%	Read
Channel 16 Test And Alarm Status		Read
Channel 16 Range And Unit		Read
Channel 17 Number		Read
Channel 17 Minimum Insulation Resistance	Ω	Read
Channel 17 Test And Alarm Status		Read
Channel 17 Range And Unit		Read
Channel 18 Number		Read
Channel 18 Symmetrical Alarm	%	Read
Channel 18 Test And Alarm Status		Read
Channel 18 Range And Unit		Read
Channel 19 Number		Read
Channel 19 DC Minus Alarm	%	Read
Channel 19 Test And Alarm Status		Read
Channel 19 Range And Unit		Read
Channel 20 Number		Read
Channel 20 DC Plus Alarm	%	Read
Channel 20 Test And Alarm Status		Read
Channel 20 Range And Unit		Read
Channel 21 Number		Read
Channel 21 ISOnet Device Timeout		Read
Channel 21 Test And Alarm Status		Read
Channel 21 Range And Unit		Read
Channel 22 Number		Read
Channel 22 ISOnet Devices Incomplete		Read
Channel 22 Test And Alarm Status		Read
Channel 22 Range And Unit		Read
Channel 23 Number		Read
Channel 23 General ISOnet Fault		Read
Channel 23 Test And Alarm Status		Read
Channel 23 Range And Unit		Read
Channel 24 Number		Read
Channel 24 DC Offset Voltage To Earth	V	Read
Channel 24 Test And Alarm Status		Read
Channel 24 Range And Unit		Read
Channel 25 Number		Read
Channel 25 Active EDS Channels		Read
Channel 25 Test And Alarm Status		Read
Channel 25 Range And Unit		Read
Channel 26 Number		Read
Channel 26 EDS Alarms		Read
Channel 26 Test And Alarm Status		Read
Channel 26 Range And Unit		Read
Channel 27 Number		Read
Channel 27 RCM Alarms		Read
Channel 27 Test And Alarm Status		Read
Channel 27 Range And Unit		Read
Channel 28 Number		Read
Channel 28 First Offline Device		Read
Channel 28 Error Status		Read
Channel 28 Value Validity		Read
Channel 28 Text Number		Read
Channel 28 Index To Text Number		Read
Channel 28 Position Text Number		Read
Channel 28 Index To Position Text		Read
Channel 29 Number		Read
Channel 29 First Offline Device		Read
Channel 29 Error Status		Read
Channel 29 Value Validity		Read
Channel 29 Text Number		Read
Channel 29 Index To Text Number		Read
Channel 29 Position Text Number		Read
Channel 29 Index To Position Text		Read
PGH Current Set	A	Read
IdN Percentage 1	%	Read
IdN Percentage 1 Channel		Read
IdN Percentage 2	%	Read
IdN Percentage 2 Channel		Read
IdN Percentage 3	%	Read
IdN Percentage 3 Channel		Read
IdN Percentage 4	%	Read
IdN Percentage 4 Channel		Read
IdN Percentage 5	%	Read
IdN Percentage 5 Channel		Read
IdN Percentage 6	%	Read
IdN Percentage 6 Channel		Read
IdN Percentage 7	%	Read
IdN Percentage 7 Channel		Read
IdN Percentage 8	%	Read
IdN Percentage 8 Channel		Read
IdN Absolute 1	A	Read
IdN Absolute 1 Response Value		Read
IdN Absolute 1 Maximum	A	Read
IdN Absolute 1 Channel		Read
IdN Absolute 2	A	Read
IdN Absolute 2 Response Value		Read
IdN Absolute 2 Maximum	A	Read
IdN Absolute 2 Channel		Read
IdN Absolute 3	A	Read
IdN Absolute 3 Response Value		Read
IdN Absolute 3 Maximum	A	Read
IdN Absolute 3 Channel		Read
IdN Absolute 4	A	Read
IdN Absolute 4 Response Value		Read
IdN Absolute 4 Maximum	A	Read
IdN Absolute 4 Channel		Read
IdN Absolute 5	A	Read
IdN Absolute 5 Response Value		Read
IdN Absolute 5 Maximum	A	Read
IdN Absolute 5 Channel		Read
IdN Absolute 6	A	Read
IdN Absolute 6 Response Value		Read
IdN Absolute 6 Maximum	A	Read
IdN Absolute 6 Channel		Read
IdN Absolute 7	A	Read
IdN Absolute 7 Response Value		Read
IdN Absolute 7 Maximum	A	Read
IdN Absolute 7 Channel		Read
IdN Absolute 8	A	Read
IdN Absolute 8 Response Value		Read
IdN Absolute 8 Maximum	A	Read
IdN Absolute 8 Channel		Read
IdL Value 1	A	Read
IdL Value 1 Response Value	A	Read
IdL Value 1 Channel		Read
IdL Value 2	A	Read
IdL Value 2 Response Value	A	Read
IdL Value 2 Channel		Read
IdL Value 3	A	Read
IdL Value 3 Response Value	A	Read
IdL Value 3 Channel		Read
IdL Value 4	A	Read
IdL Value 4 Response Value	A	Read
IdL Value 4 Channel		Read
IdL Value 5	A	Read
IdL Value 5 Response Value	A	Read
IdL Value 5 Channel		Read
IdL Value 6	A	Read
IdL Value 6 Response Value	A	Read
IdL Value 6 Channel		Read
IdL Value 7	A	Read
IdL Value 7 Response Value	A	Read
IdL Value 7 Channel		Read
IdL Value 8	A	Read
IdL Value 8 Response Value	A	Read
IdL Value 8 Channel		Read
MAC Address		Read
Current IP Address		Read
DHCP		Read and write
IP Address		Read and write
Standard Gateway		Read and write
Subnet Mask		Read and write
Modbus TCP		Read and write
Register Write Access		Read and write
ISOnet		Read and write
ISOnet Devices		Read and write
BCOM System Name		Read and write
BCOM Subsystem Address		Read and write
BCOM Device Address		Read and write
BCOM Messages Timeout	s	Read and write
BCOM Repetition Interval	s	Read and write
BCOM Percentage Change	%	Read and write
DNS Server IP		Read and write
DNS Domain		Read and write
Time		Read and write
Time Zone	h	Read and write
NTP		Read and write
NTP Server IP		Read and write
Date Format		Read and write
Summertime		Read and write
Time Format		Read and write
BS Bus Address		Read and write
Digital Input 1 Function		Read and write
Digital Input 1 Mode		Read and write
Digital Input 1 T On	s	Read and write
Digital Input 1 T Off	s	Read and write
Digital Input 2 Function		Read and write
Digital Input 2 Mode		Read and write
Digital Input 2 T On	s	Read and write
Digital Input 2 T Off	s	Read and write
Digital Input 3 Function		Read and write
Digital Input 3 Mode		Read and write
Digital Input 3 T On	s	Read and write
Digital Input 3 T Off	s	Read and write
Digital Output 1 Function 1		Read and write
Digital Output 1 Function 2		Read and write
Digital Output 1 Function 3		Read and write
Digital Output 1 Mode		Read and write
Digital Output 1 Test		Read and write
Digital Output 2 Function 1		Read and write
Digital Output 2 Function 2		Read and write
Digital Output 2 Function 3		Read and write
Digital Output 2 Mode		Read and write
Digital Output 2 Test		Read and write
Analogue Output Function		Read and write
Analogue Output Mode		Read and write
Analogue Output Midscale		Read and write
Analogue Output Test		Read and write
Buzzer Function 1		Read and write
Buzzer Function 2		Read and write
Buzzer Function 3		Read and write
Buzzer Test		Read and write
Relay 1 Test		Read and write
Relay 1 Operating Mode		Read and write
Relay 1 Function 1		Read and write
Relay 1 Function 2		Read and write
Relay 1 Function 3		Read and write
Relay 2 Test		Read and write
Relay 2 Operating Mode		Read and write
Relay 2 Function 1		Read and write
Relay 2 Function 2		Read and write
Relay 2 Function 3		Read and write
Response Value 1	Ω	Read and write
Response Value 2	Ω	Read and write
System Type		Read and write
Profile		Read and write
Coupling Monitoring		Read and write
Coupling Device		Read and write
Fault Memory		Read and write
Start Up Delay	s	Read and write
Activate Device		Read and write
DC Alarm Value	V	Read and write
DC Alarm		Read and write
EDS Current		Read and write
EDS Mode		Read and write
Portable EDS		Read and write
RS485 Protocol		Read and write
IsoData Mode		Read and write
ISOsync		Read and write
EDSsync		Read and write
ISOloop		Read and write
Share ISOloop Measured Value		Read and write
Modbus RTU Address		Read and write
Modbus RTU Baud Rate		Read and write
Modbus RTU Parity		Read and write
Modbus RTU Stop Bits		Read and write
Scan Channels		Read and write
Modbus RTU Master		Read and write
EDSsync Failure Monitoring		Read and write
EDSsync Configuration		Read and write
EDSsync Reset		Read and write
Behaviour When Inactive		Read and write
Test Command		Write
Reset Command		Write
Factory Settings Command		Write
Initial Measurement Start		Write
EDS Start		Write
EDS Stop		Write
Request ISOnet Priority		Write
Yield ISOnet Priority		Write
Start EDS Scan		Write
Acknowledge EDS Failure		Write
Save Parameter		Write
Restore Parameter		Write
Reset EDSsync Participants		Write
Device Model		Read
Article Number		Read
Serial Number		Read
Manufacturer		Read
Interface D Number		Read
Interface Software Version		Read
Measurement D Number		Read
Measurement Software Version		Read
FP200 D Number		Read
FP200 Software Version		Read

Loading registers…

Send your device list

If a device is not in the library yet, we build the template for free as soon as we have the register data.

Use cases

Show insulation resistance of every IT system on one dashboard and compare it over months.
Get an email alert when the insulation resistance drops below a threshold you choose.
Alert on the alarm status register so a pre-warning reaches the maintenance team before a second fault.
Track leakage capacitance and DC offset to see where an insulation fault starts.
Adjust response value 1 and 2 from ModbusCloud after a change in the installation.

Installation

Connect the Ethernet port of the iso685 to the same network as the ModbusCloud Gateway, or directly to its LAN port.
Note the IP address and the BCOM device address in the device menu or the COMTRAXX web interface, and check that Modbus TCP is on.
In ModbusCloud, add a Modbus TCP device with that IP address, port 502 and the BCOM device address as unit ID, and import this template.
Check that Insulation Resistance and the system voltages match the device display.

Things to watch for

The device does not answer on Modbus TCP. What should I check?

Check that Modbus TCP is switched on in the device, that the IP address is reachable from the ModbusCloud Gateway and that the unit ID matches the BCOM device address. The device handles a limited number of requests per second, so avoid reading it from several systems at the same time.

Why does insulation resistance show a very large number?

In a healthy IT system the insulation resistance can be many megaohm. Look at the range and unit register of the channel as well: it tells whether the value is exact, smaller than or larger than the shown value, or invalid.

Some registers return zero or an error. Is that normal?

Yes. Fault location, ISOnet, ISOloop and EDS values exist only in certain variants, such as the P version with EDS fault locators. On a standard iso685-D these registers stay empty.

What should I know before writing settings?

Register write access must be set to allow on the device, and the device only accepts writes with function 16. A wrong response value or profile changes when the device alarms, so agree changes with the owner. The test and reset commands only act on the documented values 64260 and 65025.

More Bender templates

All Bender templates Browse the library

Bender AbstractEvseChargePointBenderBender · Modbus TCP · 8 registers

Want to see how it works?

View demo Order your first gateway

Electrician working in an open distribution board