I brought a Banner (L-GAGE LG10 Series) Laser Gauging Sensor for a project that I'm working on. The sensor measures displacement of a moving target by emitting a laser which is then received by a PSD (position-sensitive device) receiver element. The output provides a variable of 4 to 20 mA. What I want to do is to connect the sensor to the DCS and produce trends and alarms. I am looking at a unipolar single ended analog input module (ABB AI810 Analog Input Module) to connect my sensor. I was told that I needed to use a signal conditioning system, which must convert the 4 to 20 mA current signal to a voltage signal using precision resistors. What is the purpose of this process??? why can't I just connect 4 to 20 mA output directly to the DCS???