FaultResolve
Back to Search Directory
Search this section

Search Heidenhain TNC Series CNC

Search other Heidenhain TNC Series CNC alarms without going back to the model list.

Search all database

Code 231-A920: Standstill monitoring SKERN-CC %1

Issue Description & Safety Warning

The Heidenhain TNC Series CNC has triggered a critical Standstill monitoring SKERN-CC %1 alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.

Official Troubleshooting Steps

[Cause of error] - SKERN-CC detected an impermissibly large axis movement in the SOS safety condition. The standstill speed (50 mm/min for feed axes or 10 rpm for spindles) was also exceeded. The maximum permissible path in the SOS condition is defined in the machine parameter "positionRangeVmin." Possible causes: - Machine parameter "positionRangeVmin" is defined too small. - The brake was deactivated before the position controller was closed. - The brake was not activated before the position controller was opened. - When an axis was switched on, some existing following error was corrected. - The brake is defective. - There was an attempt to move an axis in the SOS condition (PLC?) - The axis feed-rate enabling by the ApiToSafety datum PP_AxFeedEnable is missing. [Error correction] - Check the entry in machine parameter positionRangeVmin. - Check the sequence of deactivating the brake and closing the position controller. - Check the sequence of activating the brake and opening the position controller. - Check whether there is a following error after an axis is locked. - Check the interface signal of the SPLC PP_AxFeedEnable for the axis - Inform your service agency 10/2023 [475]

Source: HEIDENHAIN NC Error Messages — TNC7/640/620/320/128, CNC PILOT 640, MANUALplus 620 (10/2023)

Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.

About Heidenhain TNC Series CNC Alarms

Heidenhain controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 231-A920 on the TNC Series CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Heidenhain's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.

Complete Alarm List: 4497 Heidenhain TNC Series CNC codes.

Have a better solution?

Help the industrial community by sharing your repair experience for code 231-A920.

Manual conversion service

Need a searchable reference for more Heidenhain TNC Series CNC manuals?

We structure equipment manuals into searchable code, title, cause, solution, safety note, and source-reference data. Send a PDF and example searched codes when you need public pages, private search, or structured exports.

Convert PDF fault-code charts and manuals into clean data.
Build public SEO pages or private internal search tools.
Prioritize updates around codes and manuals people search for.
Request manual conversion Email PDFs to manuals.errordb@gmail.com
Advertisement

Space reserved for Google AdSense / Industrial Affiliate Links

Monetization target for 2026

Related Heidenhain TNC Series CNC Codes