Each DSCA42 2-wire transmitter interface module provides a single channel of 4 to 20mA process current input which is filtered, isolated, amplified, and converted to a high-level voltage output. An isolated 24V power supply is provided to power the 2-wire transmitter. Signal filtering is accomplished with a five-pole filter which is optimized for step response. An anti-aliasing pole is located on the field side of the isolation barrier, and the other four poles are on the system side. After the initial field-side filtering, the input signal is chopped by a proprietary chopper circuit. Isolation is provided by transformer coupling, again using a proprietary technique to suppress transmission of common mode spikes or surges.

The DSCA42 2-wire transmitter interface module output is either voltage or current. A dedicated loop supply is provided at terminal 3 (+OUT) with loop return located at terminal 4 (-OUT) for all current output models. The system-side load may be either floating or grounded.

Special input circuits on the DSCA42 2-wire transmitter interface module provides protection against accidental connection of power-line voltages up to 240V AC and against transient events as defined by ANSI/IEEE C37.90.1. Protection circuits are also present on the signal output and power input terminals to guard against transient events and power reversal. Signal and power lines are secured to the DSCA42 2-wire transmitter interface module using screw terminals which are in pluggable terminal blocks for ease of system assembly and reconfiguration.

Parameter Name	Parameter Value