Siemens SINUMERIK codes
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Siemens SINUMERIK Controller

Servo/Axis · Intermediate · 30-60 minutes

Alarm 6560

Siemens 840D 6560 - Data format not allowed

An attempt was made to write impermissible data in an NCK file. This error can occur in particular when the attempt was made to load binary data in the NCK as ASCII file. The error can also occur during preprocessing of cycles (see $MN_PREPROCESSING_LEVEL) if the NC block is very long. In this case,

Siemens SINUMERIKServo/AxisIntermediate30-60 minutes

6560

Siemens 840D 6560 - Data format not allowed

Data format not allowed

An attempt was made to write impermissible data in an NCK file. This error can occur in particular when the attempt was made to load binary data in the NCK as ASCII file. The error can also occur during preprocessing of cycles (see $MN_PREPROCESSING_LEVEL) if the NC block is very long. In this case,

Safety

  • Refer to Siemens documentation
  • Ensure qualified technician performs repairs

Common Causes

  • Attempting to load binary NCK data as ASCII file format
  • NC block length exceeds preprocessing limits set by $MN_PREPROCESSING_LEVEL parameter
  • Incompatible file encoding or character set in uploaded NCK file
  • Corrupted or truncated NCK file during transfer or storage
  • Mismatched data type in cycle preprocessing or custom macro definitions

Troubleshooting Steps

  1. 1Verify the source NCK file is in correct ASCII text format, not binary; use a hex editor to confirm file header and structure
  2. 2Check $MN_PREPROCESSING_LEVEL parameter setting and compare current NC block length against system limits; reduce block length or adjust parameter if within valid range
  3. 3Re-export or re-generate the NCK file from CAM software ensuring ASCII 8-bit encoding is selected; avoid Unicode or extended character sets
  4. 4Clear the NCK cache and reload the file; verify file integrity by comparing file size and checksum with original source
  5. 5Review cycle definitions and macro calls in the NC program for invalid data types or format mismatches in G-code syntax

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