Fanuc 7115 Alarm

  • Voltage check on spindle amplifier’s control input (usually 24VDC). Must be stable and within ±10%.
  • Check LED status on spindle amp:
  • Boot sequence test:
    Power CNC first, then spindle amp? (Some systems require simultaneous or amp-first power). Check machine builder’s wiring.

    • While many 7115 alarm causes are fixable in-house, certain scenarios require a factory-trained engineer.

    Call for service if:

    FANUC’s official part numbers for troubleshooting: fanuc 7115 alarm

    If your machine uses hydraulic clamps (common on B-axes or pallet changers), the pressure might have dropped slightly below the threshold while the machine was sitting idle. Boot sequence test : Power CNC first, then spindle amp

    The FANUC I/O Link is a daisy-chained network connecting the main CNC to remote I/O racks (e.g., I/O Unit A, I/O Unit B, or a handheld pendant). If a terminating resistor is missing, a cable is broken, or a slave unit (I/O module) loses power, the PMC will generate an 7115 alarm because it cannot "see" the expected hardware map. While many 7115 alarm causes are fixable in-house,

    Once you resolve alarm 7115, take these steps to ensure it never returns.

    If a machine builder created a custom macro that executes a DPRNT (Print) function or attempts to write to a PLC address that doesn't exist (e.g., W# instruction with an out-of-range byte), the CNC will halt and display 7115 with a sub-code indicating the illegal offset.