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Product description
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Festo – GDCP-CMMO-ST-EA-SY-EN – 2017-05c – English
Homing to the stop
A homing run to a fixed stop is only possible in open-loop operation (motor with encoder). The stop is
detected by a motor shutdown in combination with a sharp rise in the motor current. After that, the
stop position must be quit by positioning to the axis zero point.
Note
If the motor controller is continuously in close-loop operation against a flexible stop,
the temperature rises sharply and the controller shuts itself down. For prevention pur
poses:
Set parameters for stop detection (force limit, damping time)
Option of enabling “Position from homing point to axis zero point”.
Set axis zero point in such a way that the axis in operation, even if with a following
error, does not move to stop/limit position damping (e.g. ≥ 3mm).
Pay attention to algebraic sign on the offset (direction: away from stop).
Note
Homing to a stop: protect delicate stops by reducing the search velocity.
Note
Material damage due to moved dimensional reference system
The controller wrongly detects a stop if the actuator stops while homing, e.g.:
–
In the event of greatly reduced dynamic values (low maximum motor current)
combined with high travelling resistance (e.g. due to frictional grip)
–
At excessively low values for (lower) force limit and damping time
Adjust values so that the stop is reached.
Homing to the stop
Controlled operation
1. Search of stop with search speed in the parameterised direction:
–
Stop missing (rotary axis): actuator continues infinitely.
–
Stop not recognised: controller in closed-loop operation against the stop, shuts down if tem
perature rises above its defined limit.
2. Stop detected: position is adopted as the homing point.
3. Travel to the axis zero point
Direction: positive
Direction: negative
1)
Homing option “Position to axis zero point” must be enabled.
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Tab. 2.32
Homing method – homing to stop
