26015

Extract the MD number from alarm text (e.g., 26015 displays 'MD33010[1]'). Navigate to Siemens HMI > Diagnosis > Alarms and note the exact parameter and axis index.

Access SINUMERIK 840D NCK parameters via HMI menu: Machine > Parameters > Machine Data or use ShopMill/ShopTurn MD editor. Locate the flagged MD (e.g., MD32000 for axis geometry or MD35010 for soft limit min). Compare current value against commissioning documentation and technical manual limits.

Do not modify MD values without verified source documentation; incorrect values risk collision or axis malfunction.

Verify data type and range: Check if MD is INT, REAL, or BOOL. For numeric MDs, confirm value falls within documented min/max (e.g., MD33010 max velocity typically ≤500 mm/min on servo axes). Correct the entry and store to non-volatile memory via HMI 'Transfer' or 'Save Parameters' function.

Cycle power or execute warm restart (NCK reset) to reload MD from EEPROM. Monitor axis initialization in Diagnosis > Axis Status. If alarm persists on same MD, suspect parameter data corruption; restore from backup commissioning file or re-enter all axis geometry/limit MDs from machine nameplate.

In NCK Machine Data editor, locate MD35010 (soft limit minus) and MD35020 (soft limit plus) for the faulted axis. Verify MD35010 < MD35020. Cross-check against physical axis stroke and hardware limit switch positions documented in machine assembly manual.

Reversed or equal soft limits will always trigger 26015 on axis power-up.

Confirm both soft limit values fall within the axis mechanical range defined in MD32000 (axis length). Example: if axis has 500 mm total travel, MD35010 might be 10 mm and MD35020 might be 490 mm. Values outside this range cause validation failure.

If limits were recently changed (e.g., during setup modification), restore from the last known good commissioning MD backup file or re-enter limits based on current fixture/part geometry. Use Siemens FBNC backup utility or HMI native backup function.

After correction, trigger NCK cold restart (full power cycle) to clear cached parameter state. Verify in Diagnosis > Machine Data Validation that all overtravel MDs pass integrity check before attempting axis jog.

Identify the source of the most recent MD change: check HMI audit log (Diagnosis > System Information > Event Log) for file transfer or MD upload timestamps. Locate the import file on engineering PC or backup storage.

Open the MD source file (e.g., .txt or .csv) in a text editor and search for the flagged parameter number (from alarm text). Inspect for syntax errors: verify decimal separator matches system locale (period vs. comma), no leading/trailing spaces, and no special characters. Cross-reference with a known-good MD file from commissioning or OEM reference.

Do not directly edit .spf/.mpf files in notepad; use Siemens SINUMERIK ShopMill Editor or dedicated commissioning tool.