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General Mach Discussion / Homing position is not absolute
« on: May 01, 2011, 12:48:25 PM »
Hello everyone!
I'm not happy with the homing function in Mach3.
When starting the homing, the machine runs into the switch. It then slow down and stops. The number of steps needed to stop depends on the speed in the moment the switch is closing and the acceleration. The machine is then trying to get to full speed in the opposit direction til the the switch is released. In the moment the switch is released it will be on the same speed like the moment the switch was closed because the distance and acceleration are the same. Now the machine slow down again and stops. And after that the position is set (to zero). This position is the number of steps away from the switch-release-point of needed to come to full stop.
If the the machine is verry close to the switch before homing, may be 4 steps, it will not reach max speed, so not the max breake distance is nedded. 4 steps vor speedup means 4 steps needed to break. In this case the new zeroposition will be ca. 4 steps away from the switch-release-point.
The homingposition depends on the position from where the homing ist started. And if you change the motortuning the position will move as well.
I would like the machine running into the switch. Break and stop while counting the steps needed. As I know a switch (mechanical or optical) can't be released by now. Then travel back these number of steps. Now go on step by steb til the switch is released so the machine can stop with only one step after releasing the switch. This position will never change.
What do you think?
Burkhard (Germany)
(sorry for my bad english)
I'm not happy with the homing function in Mach3.
When starting the homing, the machine runs into the switch. It then slow down and stops. The number of steps needed to stop depends on the speed in the moment the switch is closing and the acceleration. The machine is then trying to get to full speed in the opposit direction til the the switch is released. In the moment the switch is released it will be on the same speed like the moment the switch was closed because the distance and acceleration are the same. Now the machine slow down again and stops. And after that the position is set (to zero). This position is the number of steps away from the switch-release-point of needed to come to full stop.
If the the machine is verry close to the switch before homing, may be 4 steps, it will not reach max speed, so not the max breake distance is nedded. 4 steps vor speedup means 4 steps needed to break. In this case the new zeroposition will be ca. 4 steps away from the switch-release-point.
The homingposition depends on the position from where the homing ist started. And if you change the motortuning the position will move as well.
I would like the machine running into the switch. Break and stop while counting the steps needed. As I know a switch (mechanical or optical) can't be released by now. Then travel back these number of steps. Now go on step by steb til the switch is released so the machine can stop with only one step after releasing the switch. This position will never change.
What do you think?
Burkhard (Germany)
(sorry for my bad english)