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Author Topic: Sequence operation for servo motor tuning in Mach  (Read 5240 times)

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Offline Fleck

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Sequence operation for servo motor tuning in Mach
« on: August 26, 2013, 11:58:39 AM »
I have noticed that I am loosing position on my Z axis with my gantry router. I have a stepper equipped lathe (different controller) that I have set the feeds/speeds up on by raising the feedrate as high as possible then slowly raising the start/stop and measuring movement until steps are lost at this point using 70% as a workable setting, then doing the same with max feedrate, direction change etc...

Would this "go-no-go" approach work with servos as they are closed loop? If it would what would the proper order of operations be to max out motor to the point of position loss and then back off in Mach3.
                         Thanks,
                              Mike
this is my router, there are many like it but this one is mine

Offline Hood

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Re: Sequence operation for servo motor tuning in Mach
« Reply #1 on: August 26, 2013, 01:20:29 PM »
Servos are a bit different as you know what the max RPM is or at least have a good idea what it is and thus can work out the Vel from your gearing etc (if you have any).
  For AC Servos the drive and motor combination will let you know exactly what Max RPM is , for DC motors it can be slightly different as you may be supplying the drives with a lower voltage than the max the motor can handle. However most motors will have a voltage constant value on their nameplates, this will equate to the voltage required for 1000RPM, so say the constant was 25v then if you were supplying 100v you know the motors will do approx 4000rpm. There will however be losses in the drive itself so it will be slightly lower than the voltage you actually input and thus the max RPM will be lower,  but it will be fairly close.
 The Accel however will depend on the machine the motors are connected to so that is just trial and error to get the max you can, there is however no trading between Vel and Accel with servos as there is with Steppers, what I mean by that is with steppers you can often get higher accel by dropping the Vel a bit.

Hood

Offline Fleck

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Re: Sequence operation for servo motor tuning in Mach
« Reply #2 on: August 26, 2013, 02:53:16 PM »
Thank you for the information
this is my router, there are many like it but this one is mine