- LinuxCNC
- General LinuxCNC Questions
- Difference between programmed path and actual travelling path- how to solve ?
Difference between programmed path and actual travelling path- how to solve ?
- Todd Zuercher
-
- Online
- Platinum Member
-
Less
More
- Posts: 4978
- Thank you received: 1377
24 Jan 2017 14:23 #86560
by Todd Zuercher
Replied by Todd Zuercher on topic Difference between programmed path and actual travelling path- how to solve ?
Assuming you are using step motors you need to figure out why they are loosing steps and there are lots of possible reasons. Is it because of too high acceleration, too high max velocity, marginal step space timing settings, poor control signal (3.3v parallel port connected to a drive that needs a 5v signal), electrical noise, or other wiring problems.
Please Log in or Create an account to join the conversation.
- tommylight
-
- Away
- Moderator
-
Less
More
- Posts: 18515
- Thank you received: 6184
24 Jan 2017 14:28 - 24 Jan 2017 14:29 #86561
by tommylight
Replied by tommylight on topic Difference between programmed path and actual travelling path- how to solve ?
Lower the velocity and acceleration in the ini file and test again.
Most probably that is all you have to do.
Edit:
Sorry Tod, i had it opened for a while so i did not notice your reply.
Most probably that is all you have to do.
Edit:
Sorry Tod, i had it opened for a while so i did not notice your reply.
Last edit: 24 Jan 2017 14:29 by tommylight.
Please Log in or Create an account to join the conversation.
24 Jan 2017 17:52 #86576
by viski
Replied by viski on topic Difference between programmed path and actual travelling path- how to solve ?
They don't lose steps.
I had used TurboCNC and i hadn't had this problem with it.
I have changed cycle time =0,10. Better results but still not perfect.
I had used TurboCNC and i hadn't had this problem with it.
I have changed cycle time =0,10. Better results but still not perfect.
Please Log in or Create an account to join the conversation.
- tommylight
-
- Away
- Moderator
-
Less
More
- Posts: 18515
- Thank you received: 6184
24 Jan 2017 18:39 #86578
by tommylight
Replied by tommylight on topic Difference between programmed path and actual travelling path- how to solve ?
Are you sure you have the scaling right?
Please Log in or Create an account to join the conversation.
- Todd Zuercher
-
- Online
- Platinum Member
-
Less
More
- Posts: 4978
- Thank you received: 1377
24 Jan 2017 20:51 #86581
by Todd Zuercher
Replied by Todd Zuercher on topic Difference between programmed path and actual travelling path- how to solve ?
If your scaling is right for lower speed moves but your coming up short on rapids, That is the definition of loosing steps. (and seemed to be what you were implying from your original post.)
Steps can be lost in other places besides between the motor and step driver. The motor might not be missing any of the steps it is commanded to by the driver, but perhaps the driver isn't getting all of the steps that Linuxcnc is commanding. The most likely causes of this are either step space or step hold time is too short, or a wiring/port voltage problem causing marginal signal quality (slow steps get through but fast ones don't always make it because of voltage rise times).
One thing to remember steps are not on/off for equal times for any given velocity. They are turned on for the step hold time then off for the remainder of time. Therefore unless you need really fast steps there is no advantage to specifying a very short step hold time.
Steps can be lost in other places besides between the motor and step driver. The motor might not be missing any of the steps it is commanded to by the driver, but perhaps the driver isn't getting all of the steps that Linuxcnc is commanding. The most likely causes of this are either step space or step hold time is too short, or a wiring/port voltage problem causing marginal signal quality (slow steps get through but fast ones don't always make it because of voltage rise times).
One thing to remember steps are not on/off for equal times for any given velocity. They are turned on for the step hold time then off for the remainder of time. Therefore unless you need really fast steps there is no advantage to specifying a very short step hold time.
Please Log in or Create an account to join the conversation.
- LinuxCNC
- General LinuxCNC Questions
- Difference between programmed path and actual travelling path- how to solve ?
Time to create page: 0.180 seconds