Electronic things
a short story about cnc control
This is a short story about how Karl got his brains. CNC Controllers are complex little boxes that tell the machine how and when to move. There aren't a lot of pictures for this post, mostly just the struggles of getting a a fully functional CNC controller. 

For Karl we are using LinuxCNC based control and Mesa FPGA's for IO. LinuxCNC is a really great project that provides many of the features needed for accurate and safe operation of a machine such as Karl. When paired with a Mesa FPGA a powerful machine controller can be built to suit the needs of almost any machine tool. 

Most of these control boxes start out with the best of intentions. Clean tidy wiring and a nicely laid out set of components with easy access to replace parts that may break. After having built several of these, they quickly turn into a jumble of wires without a properly sized box to put them all in. Karl does not have a properly sized box. 

The outside of the control box has a few simple meters and a power switch to activate the contactor. Also an e-stop button was placed on the front of the panel. This won't be the only e-stop button, there should be an e-stop within reach of the operator at all times for safety reasons. 

Inside the control cabinet you see a jumble of well intentioned wiring. 

This wiring provides all of the connections for spindle, control board, power supplies for the motors, limit and homing switches and motor IO. While this box doesn't look fantastic, it does work. So Karl can now move under his own power and take directions from the control machine.

We wanted a way to get some basic feedback from our Clearpath motors into the machine control. Check out the forum posting here on how we got that working using Clearpaths HLFB signals into the LinuxCNC controller. 

That's all for now and we will be updating this blog when we put Karl to work building his own Z axis components. 

Electronic things
Donny Davis 18 February, 2021
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