In machines with multi-speed spindle configurations (like those found in Mori Seiki lathes), the system uses electrical contactors to switch between different motor windings or gear ratios. The 7115 alarm is triggered when the expected feedback from these switching units does not match the commanded state. Common Causes
If your CNC machine displays the 7115 alarm, follow these diagnostic steps:
: Locate the power supplies (typically two units sitting together in the center of the control cabinet). Use a multimeter to verify that you have 24VDC output. If the voltage is low or absent, replace the faulty power supply. fanuc 7115 alarm
: This is the most frequent culprit. If the 24VDC power supply (often manufactured by brands like Izumi) that powers the relay and contactor coils fails, the switching circuit cannot operate.
: In some cases, incorrect incoming power phase sequences (especially when using phase converters) can cause internal power issues that lead to multiple alarms, including 7115 and 449 (high current). Use a multimeter to verify that you have 24VDC output
: Manually inspect the contactors for the spindle. Look for signs of burnt coils or mechanical jams that prevent them from pulling in.
Are you seeing any on the spindle drive's 7-segment LED display, such as "AL-01" or a number like "449" on the main screen? If the 24VDC power supply (often manufactured by
: Ensure your incoming power is balanced. If using a phase converter, ensure the "generated leg" is not connected to a phase that the machine uses for internal control power.
The is a spindle-related fault primarily associated with the SP Switch Control system . This alarm indicates that the CNC controller has detected an issue with the switching contactors used for spindle speed control—specifically, that they are not engaging or "pulling in" correctly during power-on or operation. Understanding the 7115 Alarm
: Incorrectly set spindle initialization parameters or winding switching settings in the ladder diagram can cause the system to look for feedback that never arrives. Troubleshooting and Solutions