[ataradov]

I have a problem with circular interpolation on the DDCSV1.1 controller. The problem shows up with any firmware, but at the moment I'm running latest Pandora-CNC.

The problem is that my machine has different steps/mm settings for X and Y axis. This seem to confuse the controller specifically on circular interpolation commands (M2/M3). The resulting arcs end up squished in exact proportion of the steps/mm settings.

Linear movements are fine and I know it is not due to steps skipping, since the issue can be seen even if no motor drivers attached to the controller. The display of the controller is enough to see the issue. Here is a simple G code:

F500
G17 G21 G90 G94 G54
G1 X100.0000  Y70.0000
G17 G3 X140 Y110 R40
M30

I expect this code to move to (100, 70) and cut a circular arc with radius 40 to (140, 110). In reality the arc ends up at (140, 103). So the X coordinate is fine, bu the Y is off the expected value.

Steps/mm on the X axis is 528 and Steps/mm on the Y axis is 630. The ratio is 0.825. And the ratio of (103-70)/40 = 0.825. I also tried other steps/mm settings just to confirm this behavior.

I'm new to CNC and may be missing something obvious, but I did quite a bit of research and it does look like a genuine bug in the controller. But A lot of people use it, and I can't find any references to this problem.

I'm aware of the thread on the MadModder forum about this controller, but their registration process required a moderator approval, and it takes a while now.

Has anyone here experienced this problem? Can you confirm the behavior if you own the controller?

[ataradov]

Ok, so apparently it is a known issue and there is a firmware that fixes it by introducing software circular interpolation. I'm attaching it here, just in case anyone needs it.

In theory recent version of the hardware does not have this problem also.