NC machine tool computer controller monitoring - uses comparison of input and output cycle times with limits

摘要

A monitoring method and circuit are used for the computer of a numerically controlled machine tool. The method involves cyclic input to the controller of one or more actual position values determined by a position measurement system. The controller produces control values from the position values and program input data and cyclically outputs control values to one or more drive units. For each actual position value input cycle a monitoring time begins and is monitored with respect to a maximum time. If the maximum time is exceeded a protection signal is triggered. A similar time interval monitoring procedure is followed for each position control value output cycle.