8520-ASM3

The 8520-ASM3 is a 3-axis analog servo module for the 8520 CNC machine, which is manufactured by Allen Bradley. It belongs to the series 9 CNC PAL family of switches. The 8520-ASM3 has two analog drive configurations, a configuration, and a lathe configuration. The mill configuration will have three axes of control, with each axis having its individual servo control as well as a feedback device, whereas the lathe configuration will have two axes of control and each axis will have a servo motor, a feedback device, and an open loop spindle with position feedback.

The servo amplifier will amplify the signal from the servo module to drive the servo motors. The positioning and velocity data is sent to the 8520-ASM3 switch from the control unit, where the 8520-ASM3 will process the data to produce the signals that drive the motors in the corresponding direction. The 8520-ASM3 has a maximum output voltage of 10 Volts and the output driver is single ended. Around 500 mV is the maximum output offset voltage for the 8520-ASM3 while the maximum output current is 5mA. The load range for the 8520-ASM3 is 2 kOhms to infinity while the load capacity is 0.01 mF. For the 8520-ASM3 switch, the resolution is 1.22 mv (13 bits + additional sign bit). To replace the 8520-ASM3, first turn off all of the connected power supplies, then disconnect all the cables that are connected to the servo module. Then remove the 4 mounting screws to remove the board rack from the component enclosure. Locate the servo board and remove the six mounting screws from the board rack to replace the board; then replace the board and mount the board rack back in place. Reconnect all the cables and turn on the power to verify proper operation.