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Access Siemens HMI > Service > Parameters > Machine Data. Navigate to MD20060 (PROTECT_ZONE_MIN_X, Y, Z...) and MD20065 (PROTECT_ZONE_MAX_X, Y, Z). Verify that the zone boundaries do not overlap legitimate part program coordinates and that min values are genuinely less than max values.

Do not modify protection zones while machine is in automatic mode or with spindle active.

Cross-reference the part program block number shown in alarm (%2) with the CAM-generated NC code. Confirm the axis coordinate values in that block and verify they should be outside the protection zone for this operation.

If protection zone adjustment is required, recalculate MD20060-MD20065 based on actual machine geometry, fixture clearance, and safe working envelope. Save parameters via HMI and perform a full machine data reload (cycle power or use NCK reset).

Verify MD20050 (PROTECT_ZONE_ACTIVE) is set to 1 (enabled); if protection should be temporarily disabled for diagnostics, set to 0, test, then re-enable.

Review the NC program listing in the Editor or via HMI > Program > Display. Search backward from the alarm block number (%2) for SETZW, CLRZW, or G25/G26 commands (zone definition syntax varies by SINUMERIK version). Note the zone corner coordinates specified.

Verify the SETZW parameters match the intended protected region geometry. If the zone is unnecessarily large or positioned incorrectly, correct the X, Y, Z min/max values in the SETZW statement and verify a corresponding CLRZW exists after the zone is no longer needed.

Insert a CLRZW command immediately before the alarm block (or at the nearest safe point) to deactivate any lingering protection zone. Re-download the part program to the control and verify the alarm no longer occurs.

If using automatic protection zone calculation (MD20080 PROTECT_ZONE_AUTO), verify this feature is intentionally enabled and that the resulting zone does not conflict with part geometry.

In the active channel, check current tool offset (HMI > Offsets > Tool Offset) and workpiece offset (HMI > Offsets > Zero Offset or G54-G59 WCS). Compare these values to those assumed in the CAM program; verify that combined geometric offset does not translate part coordinates into a protected region.

Access Machine Data MD11100-MD11120 (geometry offset values for each axis) and verify these values have not been inadvertently changed or corrupted. Compare to baseline/reference backup if available.

Temporarily clear all active offsets (set WCS and tool offset to zero via HMI Offset menu) and re-run a single block from the part program to isolate whether offset is the root cause. If alarm clears, re-apply offsets incrementally.

Once offset source is confirmed, adjust either the protection zone boundaries (MD20060-MD20065) to account for the offset, or correct the WCS/tool offset values to match the part program intent.