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General Mach Discussion / Many lost steps in CV mode for A + Z movements

« on: October 28, 2008, 02:27:14 PM »

I have a 4-axis cnc portal mill with 3 linear axis X, Y, Z and one rotary table axis A and I use Mach3 R2.63

When I run the following cnc code:

%   
G21 G17 G40 G49 G50 G80 G90 G91.1

S1500
M3 M8   

F2000

G1 X10

A80
Z-22.99
A79
Z-22.98 A50

Z-40

M5 M9
M30

then A axis hangs at "Z-22.98 A50" with many lost steps, I guess the ramps for acceleration are missing.

It seems this is a bug in Mach3 R2.63. This bug is also present in the newest versions of Mach3.

I tested it with Mach3 R1.83 and there this bug does not exist !

This bug appears only in Constant Velocity mode and only with A and Z movements (not with Z and Y moves).

It also exists with B and Z moves.

This bug also depens on how big the differnce between the two Z positions is (here 0.01 mm).

If the difference is greater than about 0.2 mm then the bug disappears.

I have tried many different settigs in Gerneral Config but the bug remained.

Can anybody try out this code ?

Here is the test file and the xml settings file:

http://members.aon.at/joshin/foren/mach3/RotaryTest.tap
http://members.aon.at/joshin/foren/mach3/RotaryMilling.xml

Josef