Code 231-81B0: DQ com error of inverter %1 Po=%4 Dev=%5 Error=%6
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical DQ com error of inverter %1 Po=%4 Dev=%5 Error=%6 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] - DRIVE-CLiQ communication to the inverter of the named axis is disturbed - DRIVE-CLiQ communication at the named output (Po=Port) has been interrupted - Error code (error) of the DSA link (third additional info): - Output in decimal, to be interpreted in binary, consisting of 8 bits: Bit(s) Meaning 7 Interrupt triggered 6..5 Error group: "00" Telegram reception error "01" Other reception error "10" Transmission error "11" Other errors 4 Telegram too early 3..0 More detailed information: 0x1: CRC error 0x2: Telegram too short 0x3: Telegram too long 0x4: Length byte incorrect 0x5: Wrong telegram type 0x6: Incorrect address 0x7: No SYNC telegram 0x8: Unexpected SYNC telegram 0x9: ALARM bit received 0xA: Life sign is missing 0xB: Synchronization error of the alternative cyclic data traffic [Error correction] - Inspect the DRIVE-CLiQ cabling - Exchange the inverter - Exchange the CC controller unit. - Inform your service agency. [408] 10/2023
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 231-81B0 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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