Superintend IMD © Copyright Muuntosähkö Oy - Trafox 7
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USE
IM-05DCCT UNIT
The IM-05DCCT unit independently measures the insulation resistance and capacitance
of the IT network to be monitored, in relation to protective earth. The measurement is
performed by feeding two summed low frequency alternating voltages between the
network and the PE conductor. These generate a low current that travels through the
insulation resistance and capacitance to be measured. The insulation resistance and
capacitance are calculated by FFT analysing the current and then measuring the
amplitude and phase. The insulation resistance values are filtered with averaging filter.
The network voltage is monitored and undervoltage conditions are detected. Connection
of the earth wires is monitored. A self test is executed automatically every 5 minutes.
The overall status of the system is signaled with status output. The measured insulation
resistance value is signaled with PWM output. In case of error, the error type is also
signaled with PWM output.
Measurement values can be monitored and settings can be changed using the CAN bus
interface.
STATUS OUTPUT
The status output signalises the overall condition of the system. The operating principle
of the status output is high side, and an external pull-down resistor is needed. The
status output has the following states:
PWM OUTPUT
Under normal conditions, the PWM output signalises the measured insulation resistance.
Under special conditions, the PWM output signalises some information about the
condition. The PWM output has two possible configurations:
