OX 48V spindle control
Background DRAFT WORK IN PROGRESS One of the first steps in setting up the OX for operation is to calibrate the spindle speed vs the "M3" values sent from the TinyG. My first set of tests revealed a non-linearity in this control function. https://plus.google.com/+DonKleinschnitz/posts/AG6gZ7Lxhs7 This caused me to start a search to find, explain and remove the spindle vs speed linearity, the subject of this post. Donate: Please consider donating (button to the left bottom of this post). Your donations help fund additional research, tools and parts that I will return to the community as DIY information. Circuit tracing The Rio Rand controller was dissembled and a schematic was created. Theory of operation The key elements of the controller's design are: PWM input source choices: external or internal generated PWM selected by jumper External PWM: an opto-coupler interfaces the external PWM to the 555 which in this mode is used as a pre-st