Fanuc 7115 - Alarm

The CNC controller commands a speed change, but the PMC (Programmable Machine Controller) does not receive confirmation that the gear or winding has switched within the allotted time.

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If these steps do not resolve the issue, specialized diagnostic services from providers like Global Electronic Services or MRO Electric can help identify deeper component failures within the spindle amplifier or control board. fanuc 7115 alarm

In the world of FANUC diagnostics, Alarm 7115 is notoriously vague. It is the CNC control’s way of saying, "I tried to move the axis, but something physically stopped me, and I don't know exactly what it is."

: If you also see a 449 alarm (high current) or EX0099 , it further suggests a systemic electrical issue or a short circuit in the amplifier/cables. The CNC controller commands a speed change, but

This means that, unlike standard FANUC servo or program alarms, the exact meaning of “7115” is . It could be triggered by a hardware fault (e.g., a missing I/O signal, limit switch failure, or communication loss) or by a software condition (e.g., a sequence timeout or a user‑programmed error check).

When you see this alarm, the CNC memory or the active program macro has encountered an instruction it cannot compute while running or simulating a Manual Guide i cycle. Primary Causes of the 7115 Alarm If you share with third parties, their policies apply

Because the encoder memory was wiped, you must re-establish the machine's reference point. The Parameter 1815 Method Switch the machine to .

At its core, the 7115 alarm is a feedback loop failure. The CNC controller sends a command to the Fanuc servo drive, which in turn moves the motor. When the actual position reported by the encoder differs too significantly from the commanded position—often due to mechanical resistance or electrical glitches—the system triggers the 7115 code to prevent damage. Primary Causes

The MCC is the component that makes a "click" sound when the spindle changes gears or ranges. Locate the MCC in the electrical cabinet. Check if it is physically stuck. Listen for a "click" during the switch.

| | 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. |