Siemens SINUMERIK codes
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Siemens SINUMERIK Controller

Servo/Axis · Intermediate · 30-60 minutes

Alarm 17030

Siemens 840D 17030 - Channel block illegal array index 2

General: A read or write access has been programmed to an array variable with an invalid 2nd array index. The valid array indices must lie within the defined array size and the absolute limits (0 - 32,766). PROFIBUS I/O: An attempt was made to read/write data outside the slot / I/O area limits of th

Siemens SINUMERIKServo/AxisIntermediate30-60 minutes

17030

Siemens 840D 17030 - Channel block illegal array index 2

Channel block illegal array index 2

General: A read or write access has been programmed to an array variable with an invalid 2nd array index. The valid array indices must lie within the defined array size and the absolute limits (0 - 32,766). PROFIBUS I/O: An attempt was made to read/write data outside the slot / I/O area limits of th

Safety

  • Refer to Siemens documentation
  • Ensure qualified technician performs repairs

Common Causes

  • Array index value exceeds maximum limit of 32,766 or is negative
  • Second dimension array index out of bounds relative to declared array size
  • Incorrect array declaration size in part program or subroutine
  • Variable reference error where wrong array variable is being accessed
  • PROFIBUS I/O slot or area boundary violation in data access

Troubleshooting Steps

  1. 1Review the part program at the indicated channel and block number to identify the array variable and index being accessed
  2. 2Verify array declaration statements match the actual array dimensions used in read/write operations throughout the program
  3. 3Check that second dimension index values stay within 0 to array_size-1 range and do not reference values beyond 32,766
  4. 4Inspect PROFIBUS I/O configuration if alarm involves slot access; confirm I/O area assignments and boundaries match program references
  5. 5Test array operations in isolation using a simple test program with known good array sizes and index ranges to isolate the problematic code section

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