Author Topic: Stepper controller velocity change  (Read 10652 times)

cch1955

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Stepper controller velocity change
« on: July 31, 2006, 02:41:41 PM »
If I issue a STEPMOVE comand can I midway trough the move change the velocity by issuing a SETSTEP command with a new velocity?

I have an application that is on a winder with a stepper driven laying axis where I need to follow the supply spool and allow for operator induced speed changes out of the PLC control loop.

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Re:Stepper controller velocity change
« Reply #1 on: July 31, 2006, 03:48:36 PM »
Yes, it is possible to issue a STEPSPEED command to change the speed while the stepper motor is already moving at constant speed. i.e. you can't change speed during acceleration/decceleration phase.

Also stepspeed change the speed without acceleration/deceleration so if the changes is abrupt then you need to change the speed in stages so as not to cause the motor to miss some steps.
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cch1955

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Re:Stepper controller velocity change
« Reply #2 on: July 31, 2006, 04:07:34 PM »
This makes my task much more simple. :)

I am mixed up some: I think you want to make sure I also include accel-decel parameter in change STEPSPEED command to make sure speed change is smooth.

If  I not include Decel-Accel parameter in SETSPEED it will be abrupt speed change and could loose motor control.

Is my understnading correct?

Thanks

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Re:Stepper controller velocity change
« Reply #3 on: July 31, 2006, 08:31:50 PM »
No. When you do a Stepspeed in the middle of a move, it just change to the new speed immediately. The acc/dcc parameters are ignored. So you have to change speed in stages if the change is very abrupt.
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