isoPV1685xxx_D00007_05_M_XXEN/02.2020
9
Function
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
R
an1
(alarm 1) and
R
an2
(alarm 2) (both
200 Ω…1 MΩ) for prewarning and alarm.
R
an1
≥
R
an2
applies.
•
Automatic adjustment to high system leakage capacitances up to 2000 μF,
selectable range
•
Connection monitoring of L+, L- for reverse polarity
•
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 device version isoPV1685P provides a locating current injector.
isoPV1685RTU
isoPV1685P
Insulation fault localisation
(locating current injector)
X
Disconnection from the mains
X
Digital inputs
X
X
μSD card
X
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 Mod-
bus RTU: The device can be switched between BMS and Modbus.
3.2 Product description
The ISOMETER® isoPV1685RTU is an insulation monitoring device for IT systems in accord-
ance 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 superim-
posed 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 pre-
warning response value
R
an1
, the "Alarm 1" LED lights and the alarm relay K1 switches. If
the value also falls below response value
R
an2
, 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 pre-
warning response value
R
an1
, the "Alarm 1" LED lights and the alarm relay K1 switches. If
the value also falls below response value
R
an2
, 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 insu-
lation fault location with mobile insulation fault locators (e.g. EDS195).