The B30A40AC Series PWM servo amplifiers are designed to drive brushless DC motors at a high switching frequency. They are fully protected against over-voltage, under-voltage, over-current, over-heating and shortcircuits. All models interface with digital controllers or can be used as stand-alone drives. They require only a single phase or three-phase AC power supply. A single red/green LED indicates operating status. Loop gain, current limit, input gain and offset can be adjusted using 14-turn potentiometers. The offset adjusting potentiometer can also be used as an on-board input signal for testing purposes when SW1-1 (DIP-switch) is ON.