Code 207908: <location>Internal armature short-circuit active
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Internal armature short-circuit active 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: Drive object: SERVO, VECTOR Reaction: NONE Acknowledge: NONE Cause: The Motor Module signals that the motor is shortcircuited through the power semiconductors (r1239.5 = 1). The pulses cannot be enabled. The internal armature short-circuit is selected (p1231 = 4): Remedy: For synchronous motors, the armature short-circuit br aking is activated if a 1 signal is present via binector input p1230. See also: p1230 (Armature short-circuit / DC brake activation), p1231 (Armature short-circuit / DC brake configuration)
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 207908 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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