What causes Siemens SINUMERIK alarm 61818?

Parameter configuration error in the machine data for the affected axis or channel. Hardware fault on the axis drive or control module. Incorrect axis assignment or configuration in the SINUMERIK machine data. Software or firmware version incompatibility. Communication fault between NC and drive system.

How do I fix Siemens SINUMERIK alarm 61818?

1. Check the SINUMERIK alarm list for any sub-alarms or related alarms active at the same time. 2. Review the machine data parameters referenced in the alarm description for the affected axis. 3. Power cycle the machine to reset transient faults. 4. Check the SINAMICS drive diagnostics for the affected axis. 5. Consult the Siemens SINUMERIK alarm manual for alarm 61818 for detailed remedy instructions.

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Siemens SINUMERIK Controller

Servo/Axis · Intermediate · 30-120 minutes

Alarm 61818

Siemens 840D 61818 - Channel Block: Axis range limits are equal

Alarm 61818 indicates that the positive and negative axis range limits (soft limits) have been configured with identical values, creating an invalid zero-span motion envelope. This occurs in the NCK axis parameter configuration where MD20110 (positive limit) equals MD20111 (negative limit), preventing any valid axis motion within the defined workspace.

Siemens SINUMERIKServo/AxisIntermediate30-120 minutes

61818

Siemens 840D 61818 - Channel Block: Axis range limits are equal

Channel Block: Axis range limits are equal

Root Cause Summary

Alarm 61818 indicates that the positive and negative axis range limits (soft limits) have been configured with identical values, creating an invalid zero-span motion envelope. This occurs in the NCK axis parameter configuration where MD20110 (positive limit) equals MD20111 (negative limit), preventing any valid axis motion within the defined workspace.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Access Siemens HMI menu: Diagnosis > Parameters > Axis Parameters > select affected axis. Locate MD20110 and MD20111 values.
2
Verify that MD20110 (positive limit) is greater than MD20111 (negative limit). Example: MD20110=+350mm, MD20111=-350mm for symmetric travel.
Do not set limits to zero or equal values
3
Correct the parameter values according to machine specification and axis geometry. Write parameters via Parameter menu or offline via SINUMERIK ShopMill/ShopTurn.
4
Power-cycle the controller (warm reset) to reload NCK axis configuration and clear the alarm.

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