Gearing Mode

NI Motion Measurement & Automation Explorer

Gearing Mode

When you start gearing, the positions of the slave and its master are recorded as their absolute gearing reference. From then on, as long as the gear ratio remains absolute, every incremental change of the master position is multiplied by the absolute gear ratio and applied to the slave axis.

Note  While changing an absolute gear ratio on the fly is allowed, you must be careful because the slave axis jumps with full torque to the position defined by the new ratio even when the master position has not changed. Similarly, resetting the position on a master axis causes its slave axes to jump to a new position relative to the new position of the master axis.

If a relative gear ratio is selected and loaded after gearing is enabled, the position of the master is recorded as its relative reference point and every incremental change from this reference point is multiplied by the relative gear ratio and applied to the slave axis or axis.

Relative gearing changes the position of the slave axis only when the master moves. It uses the length of the current move of the master axis to calculate how far to move the slave axis. At the end of the move, if the slave axis is not at the exact position, the position error is discarded. This may happen when the true target for the slave axis is a fractional position, which is impossible to actually reach. The position error can add up over time to become significant. If it become a problem, call this function with absolute gearing selected to correct for the accumulated error. The controller calculates where the slave is supposed to be relative to the offset of the master axis beginning from the position where gearing was enabled. With gearing ratios less than 1, this problem does not appear.