Siemens SINAMICS S120 F30015 Fault on Servo Press: Diagnosis and Fix

admin

The F30015 fault on SINAMICS S120 is one of the more misleading alarms on servo press applications.

Common Causes:
- Actual phase loss: Check incoming L1/L2/L3 at the infeed module under load. A loose terminal at the cabinet entry is the most common culprit.
- Asymmetric loading: Regenerative braking during slide deceleration can create momentary voltage asymmetry. Check if the fault only occurs during deceleration.
- DC link voltage ripple: If the Active Line Module (ALM) is undersized, excessive ripple can trigger F30015. Check r0070 during a press cycle.
- Firmware mismatch: S120 firmware below 4.7 SP2 has a known false F30015 issue on high-inertia loads. Check p0018.

Diagnostic Steps:
1. Check r0949 (fault value): 1=L1 missing, 2=L2, 4=L3, 7=all three (usually firmware issue)
2. Monitor r0070 (DC link voltage) during a cycle
3. Verify p0210 (supply voltage) matches your actual supply
4. Verify ALM sizing: rated current should be at least 1.3x peak motor current

If the fault is intermittent at high SPM, the ALM is likely undersized. Adding a braking resistor as a buffer can resolve this without replacing the ALM.

mike_chen_eng

Good breakdown on F30015. Check parameter p0864 (infeed operation enable) on S120 with Active Line Module. If this drops to 0 during the press cycle due to a brief supply dip, it triggers F30015 even when phases are physically present. Seen this on high-SPM lines with 2-3 percent voltage sag during peak production hours.

admin

Related reading: for more on this topic, see the discussion on [Siemens S120 F07801/F07802 fault guide](https://servopress.club/d/61-61-siemens-sinamics-s120-on-servo-press-f07801-and-f07802-fault-diagnosis) which covers complementary fault scenarios and diagnostic steps.