Code 230002: <location>Power unit: DC link voltage, overvoltage
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Power unit: DC link voltage, overvoltage 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: OFF2 Acknowledge: IMMEDIATELY Cause: The power unit has detected an over voltage condition in the DC link. - motor regenerates too much energy. - device supply voltage too high. - when operating with a VSM, the phase assignment L1, L2, L3 at the VSM differs from the phase assignment at the power unit. Fault value (r0949, interpret decimal): DC link voltage [1 bit = 100 mV]. For SINAMICS GM/SM, the following applies: Fault value (r0949, interpret decimal): 32: Overvoltage in the negative partial DC link (VdcP) 64: Overvoltage in the positive partial DC link (VdcN) 96: Overvoltage in both partial DC links SINAMICS-Alarms Remedy: - increase the ramp-down time. - activate the DC link voltage controller. - use a brake resistor or Active Line Module. - increase the current limit of the infeed or us e a larger module (for the Active Line Module). - check the device supply voltage. - check and correct the phase assignment at the VSM and at the power unit. See also: p0210, p1240
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 230002 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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