Which is best Step/Dir or Analoge for Dual feedback setup ?

Greetings,

Hello right now i am working on a boring mill and due to its size and required accuracy(Under 15 micron) i am willing to setup dual feedback system with linuxcnc. As newbie in linuxcnc i have following confusion.

-> Which command mode is will perform better in dual feedback setup -+10V analogue or step/dir for 3d contour.
-> From where i should start and how to setup

for better performance changing all ball screw, Installing new linear scale, Machine required 11nm motor but installing 14nm motors, Motor drive have encoder output.

Thank in advance
 

Thank you for this valuable tip.

And it is possible to setup X,Y,Z,W and B axis without changing kinematics ?

You can set up all those axes using the standard kinematics (trivkins)

What motors, drives and type of feedback did you have in mind?

Henk

Well i was thinking to use Invt make 3kw servo motor on all axis in velocity mode as andypugh mentioned.

For position displacement feedback 5 micron linear encoder on all linear axis and rotary encoder on rotary table and

For speed(Velocity) feedback motor encoder output from motor drive.

And a I5 minipc with Mesa FPGA board for Linuxcnc Interface

That sounds ok to me, bit I would go for 1um scales. I have used both, and there is a noticeable improvement.

I don't think dual feedback is necessary tough. Use the scale feedback for position to linuxcnc and let the drive sort out its own velocity loop

The software can only do so much though, and there is no substitute for a good mechanical system.

And make sure that the motors are big enough...

For motor we are going same way it requires 11nm but we are installing 14nm

Cause of dual feedback is size of machine saddle weight and it's boxway and have to made some 3D contour