Code 231-A890: 1st violation of negative software limit range %1
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical 1st violation of negative software limit range %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] The drive moved into the negative limit-switch range for the 1st time (machine parameter CfgAxParSafety/absLimitNeg) [Error correction] - Move the drive out of the negative limit-switch range - Check the values of the software limit switches and correct them if necessary: Machine parameters CfgPositionLimits/swLimitSwitchNeg and CfgPositionLimits/swLimitSwitchPos - Check the traverse direction of the axis and correct it if necessary: Machine parameters CfgAxisHardware/signCorrActualVal and CfgAxisHardware/signCorrNomVal and the DIR column from the motor table or CfgServoMotor/motDir
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-A890 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.
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