**RESOLVED** Velocity or Voltage Mode?

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**RESOLVED** Velocity or Voltage Mode?

Post by please no smoke »

Using mach and the mpu11, gpi04d,aftermarket drives (I'm using AMC), and brushed motors

Is it best to use voltage, velocity, or torque modes. Install manual does not say much about it that I can find.
CNCguy
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Re: Velocity or (Torque?) Voltage Mode?

Post by CNCguy »

Velocity Mode is the short answer.
The two most common methods of commanding servo drives are Velocity Mode and Torque mode.
Please see previous post:
http://www.ajaxcnc.com/ajaxbb/viewtopic ... +mode#p532

Re: Tuning Servos

Postby CNCguy » Thu Jul 15, 2010 7:37 am
Use Velocity Mode wherever you can :!: .
MPU11/GPIO4D supports velocity mode very well.
Velocity mode has fewer tuning parameters.
Velocity mode parameters are less sensitive (easier to tune).
The starting default suggested parameters will often work out of the box.

Every manufacturer or model 3rd party drive maybe slightly different.
Using Velocity mode allows the drive to handle these differences for you.
Modern (produced in the last 10 years)Third Party (non Centroid, non Ajaxcnc) AC brushless servo drives perform better in velocity mode.
This is a fact.
For more background see the post Re: Tuning Servos

Note: You most often have to set up the 3rd party drive in Velocity Mode as opposed to Torque Mode, this may be a parameter within the drive or a jumper, or maybe just which pin the command comes in on, see your drives manual.
Note: Velocity mode within the Ajaxcnc software is implied by the tuning values of( Kp, Ki, Kv1, Kg=0,Ka=0) , there is no single parameter or switch setting.
Last edited by CNCguy on Mon Oct 25, 2010 7:13 pm, edited 1 time in total.
please no smoke
Posts: 103
Joined: Mon Mar 29, 2010 10:17 pm

Re: Velocity or Voltage Mode?

Post by please no smoke »

Thanks for the info. I will try to set the drives that way.
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