Industrial Applications - Servo Motor Testing A typical ATE was designed to test servo motors. The test station was configured with quadrature decoder channels, general-purpose timer channels (differential and single-ended), digital-to-analog and analog-to-digital channels, 120 VAC relay channels and RS-422 serial communication channels. The 40-channel, high-current, high-voltage Racal Instruments VXI relay card (20A, 250VAC), was used to control the AC channels to the servo controller electronics. The servo electronics, which were controlled via the RS-422 channels, implemented velocity, position and torque modes to control the motor. The DAC channels implemented control functions while the ADC channels monitored status. Complete motor profile control was implemented through the combination of the servo controller electronics, the quadrature decoder and the timer channels.