Hello Guest it is April 17, 2021, 04:53:15 PM

Author Topic: What causes stepper motors to decelerate and then accelerate when moved?  (Read 3749 times)

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When I move the 3 axis, they  start to move and then they slow down almost to a stop, and then they accelerate up to the correct feed rate. How do I eliminate that problem?

Offline Hood

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Are you meaning jogging or via code or?
If code please attach and say approx where it happens.
Hood
When I jog and when it feeds during the program run, the motors accelerate to speed and then almost immediately, the motor decelerates to a quick stop, and then accelerates back up to speed. This happens each time the axis changes direction or begins the initial movement. How do I insert the xml file?

Offline Hood

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either copy the xml and rename it something unique or zip it with a unique name then use the additional options button on the reply page to attach.
Hood
I am sending the file.

Offline Hood

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Go into General Config and change to CV mode rather than Exact Stop.

It is always preferable to have an initialisation line in your G Code that sets modes such as CV or Exact Stop, G64 for CV.
Hood
I will try  that and let you know. Thanks for the help.
Hood,
I changed to CV, but it still happens when I rapid jog. Could it be a motor tuning problem?

Offline Hood

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I dont have a 32bit computer here to test with but will try tomorrow at the workshop if I remember ::).
Do the DROs show the axes moving like that?
What is the frequency and Time In Int on the diagnostics page?

Hood

Offline Hood

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I see you have backlash enabled and the shuttle accel on Gebneral Config seems quite big. Disable backlash and see if it helps, if it does reduce the shuttle accel.
Hood