Mode 4 shows the difference in open-loop and closed-loop ERM clicks. In closed-loop the driver automatically overdrives and brakes the actuator. In open-loop, the waveform must be predefined with overdrive and braking. The image on the left shows a closed-loop waveform and the image on the right shows the same input waveform without closed-loop feedback enabled.

Figure 2-5 ERM Closed-Loop Click Waveform (Button 1)

Figure 2-6 ERM Open-Loop Click Waveform (Button 4)