Siemens SINUMERIK codes
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Siemens SINUMERIK Controller

Servo/Axis · Intermediate · 30-60 minutes

Alarm 12390

Siemens 840D 12390 - Channel block initialization value cannot be converted

During initialization, a value has been assigned to a variable that does not correspond to the type of the variable, nor can it be converted to the data type of the variable. Overview of type conversions: - from REAL to REAL: no, INT: yes1), BOOL: yes, CHAR: yes2), STRING: - from INT to REAL: yes, I

Siemens SINUMERIKServo/AxisIntermediate30-60 minutes

12390

Siemens 840D 12390 - Channel block initialization value cannot be converted

Channel block initialization value cannot be converted

During initialization, a value has been assigned to a variable that does not correspond to the type of the variable, nor can it be converted to the data type of the variable. Overview of type conversions: - from REAL to REAL: no, INT: yes1), BOOL: yes, CHAR: yes2), STRING: - from INT to REAL: yes, I

Safety

  • Refer to Siemens documentation
  • Ensure qualified technician performs repairs

Common Causes

  • Variable declaration type mismatch in NC program initialization block
  • Incompatible data type assignment during machine startup or part program load
  • String or CHAR value assigned to numeric variable without proper conversion function
  • Corrupted or incorrectly formatted initialization value in part program or offset table
  • Parameter or variable reference points to wrong data type definition in machine configuration

Troubleshooting Steps

  1. 1Review the part program block referenced in alarm (channel %1, block %2) and verify variable %3 declaration type matches the assigned initialization value
  2. 2Check NC program for type conversion violations - confirm REAL to REAL, INT to REAL, and BOOL assignments follow documented conversion rules
  3. 3Examine machine initialization files and offset/parameter tables for conflicting data type definitions of variable %3
  4. 4Verify any custom functions or macro calls in the initialization block are not returning incompatible data types
  5. 5Load a known-good backup part program or initialize with factory defaults to isolate whether issue is program-specific or system-wide

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