Code 233850: <location>Encoder 3: Encoder evaluation, internal software error
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Encoder 3: Encoder evaluation, internal software error 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: All objects Reaction: A_INFEED: OFF2 (NONE) SERVO: OFF1 (IASC/DCBRAKE, NONE, OFF2, OFF3) VECTOR: OFF1 (IASC/DCBRAKE, NONE, OFF2, OFF3) Acknowledge: POWER ON Cause: Internal software error in the Sensor Module of encoder 3. Fault value (r0949, interpret decimal): 1: Background time slice is blocked. 2: Checksum over the code memory is not OK. 10000: OEM memory of the EnDat encoder contains data that cannot be interpreted. 11000 - 11499: Descriptive data from EEPROM incorrect. 11500 - 11899: Calibration data from EEPROM incorrect. 11900 - 11999: Configuration data from EEPROM incorrect. 16000: DRIVE-CLiQ encoder initialization application error. 16001: DRIVE-CLiQ encoder initialization ALU error. 16002: DRIVE-CLiQ encoder HISI / SISI initialization error. 16003: DRIVE-CLiQ encoder safety initialization error. 16004: DRIVE-CLiQ encoder internal system error. Remedy: - replace the Sensor Module. - if required, upgrade the firmware in the Sensor Module. - contact the Hotline. SINAMICS-Alarms Diagnostics Manual (DAsl), 03/2009
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 233850 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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