Carrige speed control

#1

I’ve been using the XY plotter to carry a custom-made print head around XY space in simple defined geometries…e.g a circle. This has worked great for a month since I assembled and got the plotter running.
Two questions:
i) Now I want to increase the carriage speed. So far, I’ve been using the default motor DIP switch positions as HHH and this gives a carriage speed of 0.25cm/sec. According to Giovani’s (GG) useful post of 3 Sept this corresponds to 1000 steps and pen travel distance 11mm. So, I figure if I want to double the carriage speed to 0.5cm/s according to GG’s post I should set the DIP switches to HHL, i.e double the distance. I did this but using the same .svg file for my circle and the same mDraw settings the carriage careered off and hit the far right Y boundary. What is this the right way to increase the carriage head speed??

ii) I use EXCEL to generate the XY co-ordinates for the simple circle – convert the XY’s to .svg format, then open and run. My EXCEL output takes 20 points to define the circle and the XY pairs go: points="5.00,0.00 4.76,1.55 4.05,2.94 2.94,4.05 1.55,4.76 0.00,5.00 -1.55,4.76 -2.94,4.05 -4.05,2.94 -4.76,1.55 -5.00,0.00 -4.76,-1.55 -4.05,-2.94 -2.94,-4.05 -1.55,-4.76 0.00,-5.00 1.55,-4.76 2.94,-4.05 4.05,-2.94 4.76,-1.55 5.00,0.00. The header of the .svg file has scaling terms such as and . What is the relationship between GG’s ”1000 steps” and these XY values. Can I control the carriage speed by the headers in the .svg file.

Any practical help on this, or pointers to what I should read up on would be a great help…!!

#2

For previous post…sorry the second last sentence should read:

The header of the .svg file has scaling terms such as and .

And by the way the plotter returned to drawing controlled circles once I set the DIP switches back to HHH …on both motors.

Jeff808

#3

I have not looked at this for a while, but I think the dip switches change the DISTANCE and hence the SPEED. That would explain the plotter trying to plot beyond its limits.

You need to find out what numbers in the SVG file can also change the distance, half it for example.

#4

The dip switches change the stepping mode between 1/8, 1/4, 1/2, or full steps. Changing from 1/8 to 1/4 steps will double the speed and the distance at the same time.

If you’re comfortable playing with the code, you could use GCode to control the plotter, and use the upgraded version of the GCode interpreter that I posted (Upgraded XY plotter - 6W laser) as it’s capable of MUCH higher speeds.

#5