Alarm |top| — Fanuc 7115
The magnetic contactors responsible for switching the spindle windings may be stuck or failing to engage.
The system is unable to complete the switch between high and low speed spindle windings. Failed Contactors:
The proximity switches or contactor auxiliary contacts that confirm the physical switch position are malfunctioning or dirty.
: Loose connections or damaged cables between the Spindle Amplifier and the gear switching contactors. Spindle Amplifier Fault fanuc 7115 alarm
Fanuc is a well-known Japanese company that specializes in the production of industrial robots, CNC machines, and other automation equipment. The Fanuc 7115 is a popular model of CNC machine used in various industries such as aerospace, automotive, and manufacturing. However, like any other complex machine, the Fanuc 7115 is prone to errors and alarms that can disrupt its operation. One such alarm is the Fanuc 7115 alarm, which is the focus of this essay.
The majority of electrical faults are connection issues. Once the machine is safe to work on, visually inspect all the cables associated with the alarming axis. This includes the thick motor power cables, the thinner encoder feedback cables, and any connectors on the amplifier itself. Look for any signs of damage, looseness, or corrosion.
Several factors can contribute to the occurrence of the FANUC 7115 alarm. Some of the most common causes include: : Loose connections or damaged cables between the
| | Common Causes | | --- | --- | | Magnetic Contactor Failure | Burned, pitted, or stuck contactor contacts; a seized contactor mechanism preventing it from switching to the correct speed range coil. | | Wiring & Loose Connections | Loose terminals, broken feedback wires from auxiliary contact blocks, or damaged vibration-prone cabling. | | Signal Feedback Issue | A missing feedback signal from an auxiliary contact that confirms contactor engagement, or a contactor switching but not sending the "done" signal back to the PMC. | | Mechanical Interference | Physical obstruction or binding in the gear-train or drawbar preventing smooth engagement into the desired range. | | Spindle Amplifier Failure | A hardware fault in the Spindle Amplifier Module (SPM), such as degraded internal components on the main control or power board. |
Once the 7115 alarm has been resolved, take these steps to reduce the chance of it recurring:
Working on CNC electrical cabinets involves high voltages that can cause severe injury or death. Always follow your facility’s Lockout/Tagout (LOTO) procedures. If you are unsure about any step, or if the alarm persists after basic checks, contact a qualified Fanuc service technician. Do not attempt to bypass safety interlocks or manipulate the machine to clear the alarm without resolving the underlying fault. However, like any other complex machine, the Fanuc
| User scenario | Fix | |---------------|-----| | After cleaning machine, oil got into fiber optic port | Cleaned with lint-free swab and IPA | | Machine sat for weeks, alarm on restart | Reseated both fiber cables → alarm cleared | | Intermittent alarm when cabinet door moved | Found loose fiber optic connector; replaced cable | | New spindle amp installed → 7115 | Needed to change serial link parameter (Pr 190? or similar) | | Random 7115 on hot days | Cooling fan on electrical cabinet failed; amp overheating |
💡 : If you need to disable the automatic switching to the alarm screen while troubleshooting, you can set parameter 3111#7 (NPA) to 1. This is particularly useful when you are monitoring other diagnostic screens in real time.
Once you have identified the cause, you can determine the appropriate solution.
The alarm indicates a mismatch between the commanded direction for Reference Point Return (Grid Approach) and the actual physical movement direction of the axis.