Originally Posted by
joeavaerage
Hi,
With that setting you effectively have no enable input to the drive, or perhaps more importantly no way to disable a servo.
It is industry wide practice to have an enable/disable input.
PN004 determines how the servo stops when disabled or Estopped, with PN004=0 it coasts to a stop whereas PN004=1 the servo decelerates
per the setting of PN005, and as PN005 defaults to 100 ms decel that is how you have set it up, minor matter.
You are confusing the settings in Mach with the electronic gearing settings within the servo.
You need to set the steps/unit, max velocity and max acceleration in Mach to some sensible numbers AND THEN LEAVE THEM ALONE.
Now you experiment with the settings within the drive that effect electronic gearing and monitor encoder outputs if you desire them.
Once you have experimented enough to know how your servo works then set the electronic gearing and LEAVE THEM ALONE.
Now you go back to Mach and tweak the settings to your desired performance.
What you don't want to do is start adjusting both lots of settings at once....you will end up hopelessly confused and in no state to choose optimum
settings.
Firstly do you use inch or metric units? Given that you have metric ballscrews then using metric units makes sense but is not mandatory.
If you use metric then may I suggest that you use 1000 steps/unit, that is Machs resolution is 1um per step. I would suggest a max velocity such that the
servo rotates at its max rotational speed, which I believe in your case is 2000rpm. With a 10mm pitch screw that equates to a velocity of 20,000 units/min.
With these numbers I would set the acceleration to 2000 units/sec2. It is highly likely that the servo can do better than that but our aim is to choose
Mach settings that make it possible to set and tune the servo and drive. You can go back later to make settings that you wish to use in practice.
If you have not made any adjustments to the numerator and denominator settings within the drive then I would guess that they are both at default of 1.
Therefore the electronic gearing is 1:1, and so 10,000 pulse are required to cause the servo to rotate one revolution. You can test that by issuing
an MDI of: G0 X10. That should cause Mach to issue 10,000 pulse if you have used the Mach setting I recommended. The question now is 'did the servo indeed
rotate one revolution?'. If it did, all well and good. If it did not you'll have to get down and dirty with the numerator/denominator settings (or molecules or
whatever the Chinese call them).
Craig