Author Topic: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders  (Read 17233 times)

0 Members and 1 Guest are viewing this topic.

Offline gravie

  • Active Member
  • Posts: 56
    • View Profile
Re: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders
« Reply #50 on: February 09, 2017, 06:46:47 AM »
https://www.machsupport.com/forum/index.php/topic,33125.msg236542.html#msg236542

the gear changing works.... not perfekt, but ist works.  i must now optimize the spindlespeed macro.

« Last Edit: February 09, 2017, 06:49:33 AM by gravie »

Offline slovenec

  • Active Member
  • Posts: 53
    • View Profile
Re: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders
« Reply #51 on: March 25, 2017, 12:41:57 PM »
Ok I have changed the servos and from Friday morning I am trying to tune the motors with no success. Now I am questioning my input data.
Please chek my calculations:

I am using Kinco servo motors and for feedback position linear scales. The resolution of the linear scale is 0.5┬Ám if I convert it is 0.0005. To get the PPR  I divide the Lead of the screw wich is 5mm with the resolution. And the PPR is 10000.

Now if I want to calculate the steps/per I just divide the 10000/5mm and then i get Steps per=2000.

If I set this parameter into the Mac3 and start auto tuning it finished but as soon as I tried to move the axis I get e-pid fault and in case I change the max error to a larger number i get sudden movements by jogging.

The transmission between ball screw and motor is with gears.

Can anybody please help me? what am I doing wrong.


Best regards

Offline mikecole

  • Active Member
  • Posts: 32
    • View Profile
Re: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders
« Reply #52 on: March 26, 2017, 05:32:36 PM »
The "steps per" value that CSMIO wants to know is "how many pulses should I expect when the ball screw rotates 360 degrees". The steps are normally supplied by an encoder on servo or ball screw shaft. In you case, using a linear scale you know that the precision is .0005mm. (ie. one pulse every .0005mm). Your ball screw moves the nut 5mm per revolution. So the correct "steps per" for your machine is 5mm / .0005 = 10k.

Mike

Offline slovenec

  • Active Member
  • Posts: 53
    • View Profile
Re: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders
« Reply #53 on: March 26, 2017, 11:54:20 PM »
Mike what is the encoder count then ?

And also thanks for your answer.


Slovenec

Offline mikecole

  • Active Member
  • Posts: 32
    • View Profile
Re: Motor tunning with CSMIO/IP-A (PID) Trouble with encoders
« Reply #54 on: March 27, 2017, 12:48:25 PM »
Sorry Slovenec for that ambiguous answer...

For your machine, the way I understand it, your "encoder count" is 10k. The "steps per mm" is 10k / 5mm = 2000.

So your calculation is correct... Are you sure there is no reduction in the gears that connect the servo to the ball screw? It is common to have a 2:1 reduction. If this is true of your machine then your "steps per mm" number will need to be 10k / 2.5mm = 4000

Mike