Bender ISOMETER iso1685FR, Manual

Function

16

iso1685FR(M)_D00002_02_M_XXEN/06.2017

•

Commissioning: 

"chapter 5.3.2 Commissioning of the ISOMETER® iso1685FRM"

•

Modbus RTU protocol: 

"chapter 6.2 Device communication with Modbus RTU"

3.3 Functional description

Insulation monitoring is carried out using an active measuring signal which is superimposed onto the IT system 
to earth via the integrated coupling. 
If the impedance value Z

e

 between the IT system and earth falls below the set response value 

Z

an

, the Alarm 

LEDs ALARM 1 and ALARM 2 light up and the Alarm relays K1 and K2 are switched.
In addition to the active method, an optional passive method can be activated which monitors the imbalance 
of the IT network by measuring the voltage between the neutral point and earth of the IT network. If the voltage 

U

N-PE

 between the neutral point and earth exceeds the set response value 

U

an

, the Alarm LEDs ALARM 1 and 

ALARM 2 light up and the Alarm relays K1 and K2 are switched.
Both measuring methods (active and passive) act in parallel to the alarm relays K1 und K2. 
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:

•

Impedance Z

e

 between the system and earth

•

Insulation fault  R

e

 between the system and earth (when the system capacitance has been set)

•

Voltage between the neutral point and earth

•

System frequency

•

Insulation fault

•

Connection fault

•

Device fault

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 when the file was created. The typical time 
needed until the maximum file size is reached is approximately 1 day. Hence, a μSD card with a memory space 
of 2 Gbytes can record data for approx. 800 days. When the maximum data limit is reached on your card, the 
oldest file in each case will be overwritten. 
If the card cannot be written to despite an inserted μSD card, a device error occurs. With this fault, relay K3 (31, 
32, 34) is not switched.
If no μSD card has been inserted, a device error notification will be sent via the BMS bus. 
The generation of the device error notification when the μSD card has not been inserted can be activated or 
deactivated by means of the DIP switch 7. (See 

"chapter 4.3 Display and operating elements"

).

The history memory that is also copied to the μSD card contains all alarms in .csv format.

 3.3.1  Insulation monitoring

3.3.1.1 Active method (SSCP)

For insulation monitoring, a sinusoidal AC measuring voltage is superimposed onto the IT system. An insulation 
fault between the IT system and earth closes the measuring circuit. If the insulation impedance between the IT 
system and earth falls below the set response value Z

an

, the associated alarm relay K1 (11, 12,14) and  K2 (21, 

22, 24) are switched. Detected insulation faults are signalled to other bus devices via the BMS bus. In addition, 
the alarm LEDs Alarm 1 and Alarm 2 light up.

The active method includes configurable interference detection. The sensitivity and duration can be configured 
via the parameters "Störgrad" (Interference level) and "Störanzahl" (Number of interferences) respectively until 
a device fault is triggered.An interference occurs when the current interference level exceeds the set threshold 
(Störgrad, i.e. interference level). If the detected fault remains uninterrupted for a time longer than that set in 
the parameter "Störanzahl" (Number of interferences) * half the measuring period (20 ms), then a device fault