Siemens SINUMERIK codes
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Siemens SINUMERIK Controller

Servo/Axis · Intermediate · 30-60 minutes

Alarm 4400

Siemens 840D 4400 - MD alteration will cause reorganisation of buffered memory (loss of

A machine data has been altered that configures the buffered memory. If the NCK powers up with the altered data, this will lead to reorganization of the buffered memory and thus to the loss of all buffered user data (part programs, tool data, GUD, leadscrew error compensation,.)

Siemens SINUMERIKServo/AxisIntermediate30-60 minutes

4400

Siemens 840D 4400 - MD alteration will cause reorganisation of buffered memory (loss of

MD alteration will cause reorganisation of buffered memory (loss of

A machine data has been altered that configures the buffered memory. If the NCK powers up with the altered data, this will lead to reorganization of the buffered memory and thus to the loss of all buffered user data (part programs, tool data, GUD, leadscrew error compensation,.)

Safety

  • Refer to Siemens documentation
  • Ensure qualified technician performs repairs

Common Causes

  • Machine data parameter modification without proper backup procedures
  • Incomplete or interrupted machine data save operation
  • Unauthorized changes to memory configuration parameters by maintenance personnel
  • Power loss or system shutdown during machine data editing session
  • Incorrect parameter values entered in buffered memory configuration settings

Troubleshooting Steps

  1. 1Do not power cycle the NCK - power loss will trigger memory reorganization and data loss
  2. 2Review recent machine data modifications in the change log to identify which parameters were altered
  3. 3Backup all buffered memory contents (part programs, tool data, GUD, leadscrew compensation) to external storage immediately using the appropriate backup function
  4. 4Restore the machine data to the previous known-good configuration before the alteration, or carefully verify the new parameter values are correct for your system
  5. 5After confirming correct machine data settings, perform a controlled NCK restart and verify all buffered data integrity post-reorganization

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