Motion Block

Description

The Set Actual Position block is used to set the current physical position of the axis. The block takes as many parameters as group size. A single axis requires one parameter. A 3 axis group requires three parameters. Additional parameter ovals are provided when a multiaxis group is chosen. Setting the Actual Position also sets the Commanded Position to be the same value to prevent unexpected motion. The Actual Position of an encoder is the sensed position. The Actual Position of a stepper motor is the number of electrical pulses that have been emitted from the controller going into the stepper motor drive or, if using closed loop methods, into the commutator, indicating the desired position. The Set Actual Position command should not be used while an axis is in motion. The Actual Position can be queries while in motion but it should not be changed while in motion. The Set Actual Position command is most often used in homing procedures which use sensors or mechanical interference to find machine features and establish a coordinate system. Note that the position parameter does not need to be zero. If a machine homes to a position regarded as the end of the range of motion the Set Actual Position block can be used to assign that position a high value.

Escapes

Setting the actual position does not generate any escapes.

Examples

This block list sets the actual position of a single axis:

This block list sets the position of a 3 axis robot where the Z axis is in an elevated, out of the way, position at the end of the homing procedure:

Related Topics

Actual Position
Positive Limit
Negative Limit
Commanded Position
Destination Position