What causes Siemens SINUMERIK alarm 61520?

Parameter or machine data configuration error. Hardware fault on the NC or drive component. Part program error or illegal command. Communication fault between NC and drive or I/O modules. Software or firmware error requiring system restart.

How do I fix Siemens SINUMERIK alarm 61520?

1. Note the complete alarm text including any axis, channel, or block number values. 2. Check for related alarms active simultaneously in the SINUMERIK alarm list. 3. Power cycle the machine to clear transient faults. 4. Review the SINUMERIK machine data for parameters related to the alarm. 5. Consult the Siemens SINUMERIK alarm manual for alarm 61520 detailed remedy.

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Siemens SINUMERIK Controller

Servo/Axis · Intermediate · 30-120 minutes

Alarm 61520

Siemens 840D 61520 - Channel block: Additional offsets not set

Alarm 61520 occurs when grinding cycles (CYCLE413, CYCLE420, CYCLE433) attempt to execute on a 840D control without the required number of Tool Data Attributes (TDA) parameters configured. The NCK cannot allocate sufficient additional offset memory for the grinding operation, causing the block to fail before execution.

Siemens SINUMERIKServo/AxisIntermediate30-120 minutes

61520

Siemens 840D 61520 - Channel block: Additional offsets not set

Channel block: Additional offsets not set

Root Cause Summary

Alarm 61520 occurs when grinding cycles (CYCLE413, CYCLE420, CYCLE433) attempt to execute on a 840D control without the required number of Tool Data Attributes (TDA) parameters configured. The NCK cannot allocate sufficient additional offset memory for the grinding operation, causing the block to fail before execution.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Access the NCK control panel and navigate to Diagnostics > Machine Data > MD18094 or use MDI command MD(18094). Record the current value.
2
If MD18094 is less than 10, set it to MD18094 = 10 (minimum for grinding cycles). If grinding requires dressing or multi-axis compensation, increase to 15-20 as per application requirements.
Modifying MD18094 requires CNC power cycle after parameter change to reload NCK memory allocation tables.
3
Verify the change persisted by reading back MD18094 and confirm it equals your set value.
4
Execute the grinding cycle (CYCLE413, CYCLE420, or CYCLE433) on a test block to confirm alarm 61520 is cleared.

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