CountsPerUnit Parameter

The CountsPerUnit parameter specifies the number of feedback counts per primary programming unit. You can use fractional values. This parameter scales all axis-based distances, velocities, and accelerations.

Always set this parameter to a positive value. If you want to change the program direction of an axis, use the ReverseMotionDirection Parameter.

Machine Setup automatically configures CountsPerUnit for your system. If you configure this parameter without Machine Setup, know the information that follows:

• For open-loop stepper systems, set the CountsPerUnit parameter equal to the number of stepper clock pulses per primary unit.
• For stepper systems that use feedback, set it to the number of feedback counts per primary unit.

• For the Linear (R) axis of a gantry using Decoupling Control, this parameter has the same value as it would for the physical Spar 1 and Spar 2 axes if they were configured as individual stages. Note that, under Decoupling Control, Spar 1 and Spar 2 must have the same feedback resolution.

• For the Theta (Yaw) axis of a gantry built from rotary stages and using Decoupling Control, this parameter has the same value as it would for the physical Spar 1 and Spar 2 axes if they were configured as individual stages. Note that under Decoupling Control, Spar 1 and Spar 2 must have the same feedback resolution.

• For gantries built from linear spars and using Decoupling Control, use one of the formulas in the table that follows to determine the CountsPerUnit value of the gantry Yaw (Theta) axis. In the formulas, the GantryFeedbackSeparation of the Linear (R) axis is as follows:

  • For linear rigid gantries, use the distance between the spar feedback devices in millimeters

  • For linear flexible gantries, use the distance between the flexible rotary joints in millimeters

Unit	CountsPerUnit
degrees
radians
mradians
µradians
revolutions