Code 207970: <location>Drive: Automatic encoder adjustment incorrect
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Drive: Automatic encoder adjustment 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
Message value: %1 Drive object: VECTOR Reaction: OFF2 (NONE) Acknowledge: IMMEDIATELY SINAMICS-Alarms Cause: A fault has occurred during the automatic encoder adjustment. Fault value (r0949, decimal): 1: Current controller limited 2: Motor shaft locked. 4: Encoder speed signal not plausible. 10: Stage 1: The ratio between the measured current and zero current is too low. 11: Stage 2: The ratio between the measured current and zero current is too low. 12: Stage 1: The maximum current was exceeded. 13: Stage 2: The maximum current was exceeded. 14: Current difference to determine the +d axis too low. 15: Second harmonic too low. 16: Drive converter too smal l for the measuring technique. 17: Abort due to pulse inhibit. Remedy: Re fault value = 1: Check whether the motor is correctly connected. Check whether motor data have been correctly entered. Replace the Motor Module involved. Re fault value = 2: Open the motor holding brake (p1215) and bring the motor into a no-load condition. Re fault value = 4: Check whether the speed actual value inversion is correct (p0410.0). Check whether the motor is correctly connected. Check whether the encoder pulse number (p0408) and gearbox factor (p0432, p0433) are correct. Check whether the motor pole pair number is correct (p0314). Re fault value = 10: Increase the value for p0325. Check whether the motor is correctly connected. Replace the Motor Module involved. Re fault value = 11: Increase the value for p0329. Check whether the motor is correctly connected. Replace the Motor Module involved. Re fault value = 12: Reduce the value for p0325. Check whether motor data have been correctly entered. Re fault value = 13: Reduce the value for p0329. Check whether motor data have been correctly entered. Re fault value = 14: Increase the value for p0329. Re fault value = 15: Increase the value for p0325. Re fault value = 16: De-activate traversing/moving (p1982). Re fault value = 17: Repeat traversing.
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 207970 on the SINUMERIK 840D CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4014 Siemens SINUMERIK 840D CNC codes.
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