Mach2 add wrong +0.01mm to every move?

[LZ1TWB]

I have noticed this strange problem with mach2 that it adds around 0.01mm in the positive direction when realising every move. You can imagine what happens after some hundreds of lines of G code.
I had spent plenty of time wondering why the work did not looked like the programmed . Finally I put the micrometer on one of the axis and wrote a simple test code that looks like this:
G90
G1X1.0F500
X0.0
X1.0
X0.0
X1.0
X0.0
....and so on 100 lines
After that I was wrong with 1mm in +
I ran the same file in mach3 and it runs perfect, no such thing.
Anyone could say something about that? Thanks,
Todor

[paulC]

Think it can only be lost steps due to differences in motor tuning.
Try reducing the Acceleration and start velosity in the axis configuration screen of Turbocnc.

Paul

[LZ1TWB]

I am using MACH cnc software, not the Turbocnc. Anyway i think it is not the motor tuning, as I have put the same setting which are working on the other version. And the problem is that I do not have lost steps, I have one additional on every move.
In the begining I thought it is something to deal with rounding numbers. For example 1.005 to go as 1.01 or something like that. It is not that as I have tried with integers, still the same. Then i thought since 10 never divides equally by 3 It cannot calculate the necessary steps, as my screw is 3mm/r. It was not that either. Interesting...

[ger21]

Originally Posted by LZ1TWB I ran the same file in mach3 and it runs perfect, no such thing.

Then why use mach2? Bug fixes and development on it stopped almost 2 years ago?

[paulC]

Originally Posted by LZ1TWB I am using MACH cnc software, not the Turbocnc. .

Sorry. I must be having a brain fade. Thought you were comparing Turbocnc with Mach3.
As Gerry says. Why would you spend all the effort on Mach2 if Mach 3 works for you?
Paul

[Torchhead]

Seems to me there were some direction change parameters that we had problems with like you describe in MACH2....the cure was to increase the Dir change time in mototr tuning (I think) but as the others said it's like worring if Lincoln was shot once or twice...he's still dead (;-)

[LZ1TWB]

Yeah, you are so right about using mach3 as it is much better but I have seen so many people on the net using the "2" ver and I don't think they will continue with it if experiencing the same problem.
Maybe the Dir change time is also to do with this as I saw that mach3 gives me the chance to set a bit higher value for it.