Clearing the Limit Switch

After the limit switch is triggered, it must be cleared by moving the axis in the direction opposite to the limit switch.

The limit switch action that is set with the LS Type, Near LS Type, External LS Type, or Soft Limit Type parameter will be executed only on the rising edge of the limit switch. Therefore, the axis servo can be turned on and commanded after the limit switch action completes.

As long as the limit switch signal remains on (and the LimitSwitchType is not None), any position commands in the direction of the limit switch will be canceled by the WMX3 engine. The limit switch can be cleared by commanding the axis to move in the direction opposite to the limit switch using any motion command.

The following figure shows the motion of the axis as the limit switch is triggered and then cleared.

Depending on the configuration of the limit switch, it is possible for the limit switch signal to turn off before the limit switch action completes. A near limit switch that is set to the Dec LimitSwitchType might turn off if the axis moves out of the trigger range of the near limit switch while decelerating. If this occurs, the WMX3 engine will not cancel position commands in the direction of the limit switch.

When moving the axis back to the range of normal positions, the limit switch action that is set by the LimitSwitchType will not be executed even if the limit switch signal turns on again. Positive limit switches do not trigger while the axis command position is moving in the negative direction, and negative limit switches do not trigger while the axis command position is moving in the positive direction.

The following figure shows the motion of the axis when the limit switch is triggered, and then the limit switch signal turns off while the axis is decelerating, and then the limit switch is cleared.