Bender A-Isometer IRDH 275, Operating Manual

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11 TGH1361en/11.2009
2. Function
2.1 Common characteristics (IRDH275 and IRDH275B)
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A-ISOMETER® for IT AC systems with galvanically connected rectifiers
and for IT DC systems (IT = unearthed systems)
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The operating range of the nominal voltage U
n
can be extended via coupling
devices.
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Automatic adaptation to the existing system leakage capacitance
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measuring principle (European Patent: EP 0 654 673 B1)
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Two separately adjustable ranges of the response value1 k
Ω
...10 M
Ω
(Alarm 1, Alarm 2)
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Two-line LC display
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Connection monitoring (monitoring of the measuring leads)
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Automatic device self test
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Option "W":
This option provides: improved shock and vibration resistance for use in ships,
on rolling stock and in seismic environment.
2.2 Additional characteristics IRDH275B
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Memory with real-time clock to store all alarm messages with date and time
stamp.
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BMS interface (BMS protocol) for data exchange with other Bender devices
(RS485 electrically isolated).
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Internal disconnection of the A-ISOMETER from the IT system to be monitored
(using a control signal; terminals F1/F2) , e.g. if several A-ISOMETERs® are inter-
connected.
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Current output 0(4)...20mA (galvanically separated) in relation to the meas-
ured insulation value.
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Remote setting of certain parameters via the Internet (option; FTC470XET
additionally required)