Siemens SINUMERIK codes
AxisMD

axismd.ai

Siemens SINUMERIK Controller

Program/G-code · Intermediate · 30-120 minutes

Alarm 400903

Siemens 840D 400903 - Parameter IntNo impermissible in FC 9

Siemens SINUMERIK alarm 400903: Parameter IntNo impermissible in FC 9. An impermissible or invalid parameter was passed to PLC function block FC9. This indicates a PLC programming error or configuration mismatch in the machine tool builder ladder program.

Siemens SINUMERIKProgram/G-codeIntermediate30-120 minutes

400903

Siemens 840D 400903 - Parameter IntNo impermissible in FC 9

Parameter IntNo impermissible in FC 9

Siemens SINUMERIK alarm 400903: Parameter IntNo impermissible in FC 9. An impermissible or invalid parameter was passed to PLC function block FC9. This indicates a PLC programming error or configuration mismatch in the machine tool builder ladder program.

Safety

  • Refer to Siemens documentation
  • Ensure qualified technician performs repairs

Common Causes

  • Invalid parameter value passed to FC9 in the PLC program
  • FC9 called with a parameter that exceeds the valid range for this SINUMERIK configuration
  • PLC program version mismatch — FC9 call parameters not updated after a machine configuration change
  • Number of configured spindles in SINUMERIK does not match the FC9 parameter
  • PLC program downloaded with incorrect machine data for this specific machine tool

Troubleshooting Steps

  1. 1Check the SINUMERIK PLC alarm details for the specific parameter value that caused the error.
  2. 2Review the PLC program — find the call to FC9 and verify the parameter values are within valid range.
  3. 3Compare the FC9 parameter against the actual number of configured spindles in the SINUMERIK machine data.
  4. 4If the PLC program was recently modified or the machine configuration changed, verify FC9 calls were updated accordingly.
  5. 5Contact the machine tool builder if the PLC program source is not available for review.

Seeing Multiple Alarms?

Seeing another alarm with this one? Enter the code.

Get machine-aware diagnosis

AxisMD logs alarms against your actual machines, tracks patterns, and gives AI context your manual doesn't have.

Start free

Was this guide helpful?

Always verify with your machine manual or a certified technician before performing service procedures.