The KEP SC-II signal conditioner is a loop powered isolator whose function is to provide a retransmitted, galvanically isolated 4-20 mA output signal in response to isolated 4-20 analog input. The loop powered isolator may be applied in a similar manner as a conventional two wire transmitter.
The SC-II appears to the input loop as a series shunt resistor. A small sense resistor is used to measure the input current. The input loop derives it’s power from the input current loop.
This input current signal is then scaled and converted to a 0 to 10,000 Hz frequency signal by a Current to Frequency Converter. This frequency signal is then transmitted across an optoisolator to the output stage.
The output stage derives it’s power from the output current loop. The output stage converts the 0-10000 Hz frequency signal into a current flowing in the output loop equal to that flowing in the input current loop. The 10-50 mA range options are provided to enable the unit to perform range conversions as well as signal isolation.
