Code 231-C6E0: Amplitude test in axis %1: speed encoder is incorrect,
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Amplitude test in axis %1: speed encoder is incorrect, 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
test %4 [Cause of error] The internal test of encoder-amplitude monitoring at the speed inputs revealed an error: Test 1: The test for "Amplitude too low" failed. Test 2: The test for "Amplitude too high" failed. - The entry in pwmSignalOutput/analogOffset does not match the wiring of the speed encoders. - Incorrect entry in machine parameter motEncType (e.g. Z1track operation selected for EnDat2.2 encoder) - Speed encoder cable is interrupted, or encoder cable is defective - Speed encoder is defective - CC controller unit is defective [Error correction] - Compare/Check the entry in MP pwmSignalOutput/analogOffset to the speed encoder cabling - Check the entry in machine parameter motEncType - Check the speed encoder cable / Exchange the cable - Exchange the speed encoder - Exchange the CC controller unit - Inform your service agency [514] 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-C6E0 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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