In SX Microcontrollers, SX/B Compiler and SX-Key Tool, rmayhew wrote:

I've worked with plasma cutters as well as robotics and plasma welders (column or beam welding ).  I've seen a very old line burner demonstrated ( the type that has a scanner and follows a drawing on paper ).
    This machine I've built is just for hobby. I broke the arbor shaft while engraving a horse into wood so it must be repaired. I'm also rebuilding new X and Y axis, beefing them up because they're single rails now. Tomorrow I'll try to include a photo of the machine, electronics, and some projects. 

     Right now the resolution is based on 1920 pulses per inch, in the vb code find all the 1920 conversions that are transmitted and change them to the resolution you need.

     I lean toward electronics and must conclude that this, as a stepper project, will probably move to slow for plasma cutting, but the speed may be ok for fusion (plasma) welding.

     An idea I've been thinking about is switching up to a servo drive that allows quadrature input such as the Ultra 100 drive. Speed and heat would then not be a problem then but to turn a circle with the sx I used the Cordic method to buffer coordinates. As the source will show, the smaller the circle the more interations it takes to develope a new linear move. This was based on a thereom that in machining, small moves wouldn't be too small, and one would lean toward cutter comp making radius around sharp edges no smaller than the tool diameter.

     I'll post updated vb code shortly in a seperate message leaving the original.

     Improvments:

         Offset also adjusts output.

         Size control also sizes output.

         Quick home takes into account offset.

         Code to convert shades to seperated bitmaps for coding to NC. Samples provided.

         A position retrans for missed handshakes. (machine hanging)

     To Do:

         Offset hard entry form.

         

     Facts:

         This started as a parallel port project one pin on the sx was for clock and another pin for direction, per axis. Motion was lowsey at best, but it did work.

         There are 72, 16 bit word variables used in the program 80+, 8 bit variables.

         I tried to transmit a circle in streight lines over RS232 point by point, don't bother.

         The first HP calculators that had trig functions relied on the Cordic method to resolve functions.

         Memory was expensive leading to the development to Cordic method functions, as it became less expensive the method turned to look up tables to free up the processor over head.

         Now processors are getting so fast that the Cordic method is an alternative to a coprocessor call.

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