What is the standard controller output range and what does it represent?

Standard controller output is 4-20 mA (analog) or 0-100% (digital), representing the commanded position or action of the final control element. 4 mA/0% typically corresponds to valve closed (or minimum action), and 20 mA/100% to valve fully open (or maximum action). This range allows detection of signal failures (below 4 mA indicates fault). The output is scaled to the final element - for a valve, it represents demanded position; for a VFD, speed setpoint.