RE: [CAD_CAM_EDM_DRO] Re: Using linear encoders.

Sorry to say that I disagree totally with your reply. I am currently
using an Enco mill (Bridgeport Clone), with Rutex step and direction
drivers with linear encoders on the table. The system originally had an
Anilam Crusade control and when that developed problems, I converted to
Mach2 as the control. I have not had any problem getting the backlash
out due to the ballscrews that were installed in this system and it is
very stable. I can achieve 100ipm travels. The system is much easier
to calculate steps for as you only need to know the counts per inch
generated by the encoders. This has been a great system and I don't
think it was any more difficult than using encoders on the motors.
Larry

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Pete:

Such machines do exist but they are very expensive and clearly out of
the hobby price range. What you are describing is a very complex motion
control system. The major problems to overcome are loop stability and
velocity control. Even with very fast scales most designs still depend
on shaft encoders or tachometers for velocity control.

The two most popular software drivers, Mach2 and TurboCNC can not do
this. Unless one has a LOT of experience in motion control system design
(and a lot of money) this will not work. The hunting problem you mention
is the loop stability problem I am refering to and it's a bear to solve.
Stick with shaft encoders and save a lot of headaches.

Sorry for the bad news;

Ken