Haas Alarm: 147 Z LIMIT SWITCH – Axis hit limit switch or switch disconnected. Home switch input changed state while machine was in use. Stored stroke limits should stop the slides before they hit the limit switches. Verify the value of Parameter 127, Grid Offset, and check the wiring to the limit switch. Can also be caused by a loose encoder shaft at the back of the motor or coupling of motor to the screw. Z limit switch may need replacement.