2 wire active analog transmitter

Deyoung

Hi Mate,

Please find the 2-wire connection diagram attached

However, note that the terminal connection depends on the type of 2-wire sensors either a Sink or Source type and the load is connected to the output lead that sources or sinks the conventional current.

Since the conventional current flows from positive to negative of the senor, therefore,

Source Type Sensor: The load terminal is connected to the negative.

Sink Type Sensor: The load terminal is connected to the positive.

 Note that the Original Poster's requirement is for wiring a field instrument with an active 4-20mA output (also called a 4-wire device), which means that the 4-20mA signal is powered by the field instrument itself from power supplied to the field instrument, independent of any AI connection..

In the Siemens world, a 2-wire analog input is intended for a loop powered field instrument (also called a passive output) that will be powered from the Siemens analog input card, that is, the DC voltage required to power the field instrument is provided by the AI card. 

A 4 wire, active 4-20mA output requires wiring to a passive analog input that does NOT provide DC power to the field device.  A passive analog input just reads the 4-20mA signal and does not power the field device.

Wiring a 4-wire active field device to a Siemens 2-wire input will not provide a usable analog input signal.