4034

Access Siemens SINUMERIK 840D HMI menu: Diagnostics > Machine Data > MD 31010 (INTERPOLATION_TIME_MS) and note the current interpolation cycle time in milliseconds.

Query all linked NCU systems via NCK communication parameters (MD 39000-39999 range) to identify the slowest interpolation cycle time configured on any slave/linked NCU.

Verify link configuration in MD 39010 (LINK_NCU_NUMBER) and associated link parameters.

Modify MD 31010 on the local NCU to match or exceed the slowest interpolation cycle time detected in the linked NCU ensemble. For example, if a slave NCU runs 12ms cycles, set the master to minimum 12ms.

Reactivate machine parameters (Diagnostics > Machine Data > Activate) and reset the NCU. Verify alarm 4034 is cleared and monitor system synchronization via Diagnostics > Axis Information.

Parameter activation requires NCU in offline mode; moving axes are disabled during this operation.

Navigate to Diagnostics > Axis Configuration and verify which axes are declared as local link axes (check axis parameters for LINK_AXIS_NUMBER or equivalent configuration flags).

Document all linked NCU system interpolation cycles by reviewing MD 31010/31020 values on each connected NCU and create a timing matrix to identify the maximum (slowest) cycle time.

Use SINUMERIK remote diagnostics or direct HMI access to each NCU if multi-system setup is present.

Adjust MD 31010 (INTERPOLATION_TIME_MS) on the affected NCU to equal the slowest cycle time identified. Do not set faster cycles on any NCU in the link group.

Clear alarm 4034 by resetting the NCU (Diagnostics > Reset or power cycle). Confirm all axes respond to motion commands and synchronized interpolation is achieved.

Review MD 39010 (LINK_NCU_NUMBER), MD 39020 (LINK_NCU_CYCLE_TIME), and related link configuration parameters to verify all NCU system identifiers and cycle times are correctly entered.

Refer to Siemens SINUMERIK 840D documentation for complete MD 39xxx parameter range definitions specific to your system version.

Confirm that the slowest interpolation cycle time value has been explicitly propagated to all NCUs via link synchronization mechanism (typically via MD 31010 update across the link group during commissioning).

If using real-time Ethernet (PROFINET) or other link media, verify communication status in Diagnostics > Communication > Link Status to ensure all NCUs are synchronized and responsive.

Communication delays or link failures may prevent proper cycle time synchronization; resolve link faults before retrying parameter activation.

Contact Siemens support or refer to machine builder commissioning documentation to validate multi-NCU link configuration matches original design specification before re-activating local link axis configuration.