The 8520-1APA1 is an Allen-Bradley product. The 8520-1APA1 is a processor module that belongs to the 9/Series CNC Hardware. The 8520-1APA1 processor module works for both the analog as well as the digital CNC systems. The processor module used to configure the control is only 9/230. This 9/230 analog control can be purchased as a three-axis controller or a single axis controller. These individual analog servo amplifiers are used for amplifying the 9/230 processor to deliver power necessary to drive the servo motors. The control over the processor module aids the running of the servomotors with optimum performance. But the maximum feed-rates are limited in a frame according to the mechanical abilities of the machine. The 8520-1APA1 provides approximately +/- 10 Volts analog command output. This output is in turn used for up to four drive amplifiers. Additionally, the 8520-1APA1 should be kept in isolation from the digital servo amplifier as the amplifier generates electrical noise that may disrupt the functioning of the 8520-1APA1. The test points that are the small metallic pins used for troubleshooting and testing for the proper wiring are also present on the 8520-1APA1 circuit board. The connectors are also present on the processor module only. This 8520 series digital servo module functions as a high-speed servo processor and is installed in the component enclosure. These digital servo amplifiers translate low-level PWM signals from the 8520 digital servo modules to the power levels necessary to drive the servo motors.