Motion / Motor Command / Linear & Rotational Axis Commands

The following table lists the Motor Commands intended for use for linear and some rotary defined Axes .

*All position command operands values are in the units defined in the Axis assigned to the motor for the selected Slot. For a linear axis, these are typically distance (mm or in.) or encoder counts. For a non-sectored multiple rotation rotary axis, the define units are in rotations.

*Upon the first execution of the Configure Axis command, the current rotor position is set to 0 (zero). The Configure Axis instruction is designed to be included in the Main Program Initialization block prior to the executing of the Main Loop. The 0 (zero) position can also be re-established from within the Main Loop with program logic by executing the Configure Home and/or Set Motor Operation commands.

*All operands for these commands accept signed values for the Axis units to indicate direction. Positive values are in the direction of increasing units and negative values are in the direction of decreasing units based upon the defined 0 (zero) position.

Relative vs. Incremental Motion

We will use an example to illustrate the difference between Relative and Incremental motion commands.

In this example we are starting with a linear axis and we have issued an Absolute command to move to Axis position 7.
After the the move is finished, external forces on the mechanism have caused the rotor to move to Axis position 4. Even though the actual position of the rotor is at Axis position 4, the previously commanded position is still Axis position 7
For an Incremental move, the starting point is the last commanded position. Even though the actual rotor is at position 4; an Incremental move command of 5 units will result in the rotor moving to position 12 (7 + 5 = 12)
For a Relative move, the starting point is the current actual rotor position. In our example, a Relative move command of 5 units will result in the rotor moving to position 9 (4 + 5 = 9)