Code 201684: <location>SI Motion: Safely limited position limit values interchanged
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>SI Motion: Safely limited position limit values interchanged 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: SERVO, VECTOR Reaction: OFF2 Acknowledge: IMMEDIATELY (POWER ON) Cause: For the function "Safely-Limited Position" (SE), a lower value is in p9534 than in p9535. Note: This fault does not result in a safety stop response. Fault value (r0949, interpret decimal): 1: Limit values SLP1 interchanged. 2: Limit values SLP2 interchanged. Remedy: Correct the limit values in p9534 and p9535 and carry out a POWER ON. Note: SI: Safety Integrated SLP: Safely-Limited Position / SE: Safe software limit switches
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 201684 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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