[rwood359]

Does the operation work if the arm is moving very slowly? Remember that the limit switch is only being tested once for each execution of the loop. If the limit switch is only set for a small period, it is possible for the switch to be set and then rotate past to the point that it is not set between executions of the loop. When you are using a limit switch, you will find that the ending position will not be exactly the same each time that the limit is reached. The speed of the arm and repetition rate of the loop cause some uncertainty.