Siemens SINUMERIK 840D Error Code 25000

Siemens CNC Major Motor

Model: SINUMERIK 840D | Code: 25000

Applicable Systems
S7-1200 S7-1500 S7-300 S7-400 LOGO! SINAMICS

Symptoms

The CNC system displays alarm 25000, indicating an axis fault. The affected axis has lost its reference point or position data, and cannot be moved until the reference point is re-established.

Possible Causes

  • Axis encoder feedback signal lost due to cable damage or connector issue
  • Drive module for the affected axis reported an internal fault
  • Reference point switch malfunction or misalignment
  • Axis was moved manually or by external force while power was on without encoder feedback
  • Drive bus communication interrupted during axis motion

Troubleshooting Steps

  1. Step 1: Identify which axis is affected from the alarm text
    Alarm shows the specific axis designation (e.g., X, Y, Z)
  2. Step 2: Check the encoder cable at both motor and drive ends
    Cables securely connected, no visible damage
  3. Step 3: Check the drive module status LED for the affected axis
    Green READY LED on; no red fault LED
  4. Step 4: If cable and drive are OK, re-reference the axis using the reference point approach
    Axis successfully returns to reference point and alarm clears
  5. Step 5: If reference switch is suspect, check switch continuity with a multimeter
    Switch changes state when the dog passes the cam

How to Reset

To reset: 1) Fix any cable or drive issue. 2) Re-reference the affected axis. 3) Press RESET on the HMI. Caution: Re-referencing may require jogging the axis to a safe position first.

Common Replacement Parts

  • 6FX5008-5CA00-0AA0: SINUMERIK encoder cable (Use Siemens genuine cable for reliable position feedback)

Frequently Asked Questions

  • Q: What happens when an axis loses its reference point?

    The NCK cannot calculate the axis position without a valid reference point. Alarm 25000 appears and the axis is disabled until re-referenced. This protects against uncontrolled motion based on incorrect position data.

  • Q: Do I need to re-reference all axes or just the affected one?

    Only the axis showing alarm 25000 needs re-referencing. However, if the cause was a power interruption or drive bus failure, check all axes for potential position loss.

Related Siemens Fault Codes

Source: Siemens SINUMERIK 840D Diagnosis Manual (Function Manual), 2023

Category: CNC