Transmitter input module SCM7B35-02

insulated2-wireloop-powered

SCM7B35 current input modules accept input signals in the 4-20mA range from the field and provide a high-level voltage output to the process control system. Current to voltage conversion occurs internal to the module, which is factory calibrated to ensure the highest accuracy. Loop power is provided by the module, enabling a 2-wire transmitter to be directly connected without the need for a separate dc power supply for the 2-wire transmitter. These modules incorporate a five-pole filtering approach to maximize both time and frequency response by taking advantage of both Thomson (Bessel) and Butterworth characteristics. One pole of the filter is on the field side of the isolation barrier; four are on the process control system side. After the initial field-side filtering, the input signal is chopped by a proprietary chopper circuit and transferred across the transformer isolation barrier, suppressing transmission of common mode spikes and surges. The signal is then reconstructed and filtered for process control system output.