Code 206205: <location>Infeed: Voltage dip in at least one line supply phase
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>Infeed: Voltage dip in at least one line supply phase 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: A_INF, S_INF Reaction: NONE Acknowledge: NONE Cause: Voltage dip or overvoltage in one or several line supply phases has been detected in operation. The pulses are then inhibited for a time of at leas t 8 ms. The operating signal of the infeed unit in r0863.0 remains and the pulse inhibit due to the phase failure is displayed in r3405.2. Alarm value (r2124, bitwise coded cause of the alarm): Bit 0: Line angle deviation (limit va lue p3463) due to a line supply fault Bit 2: Active current deviation Bit 3: Line frequency deviation (limit values: 115 % * p0284, 85 % * p0285) Bit 4: Line overvoltage (limit value 120 % * p0281 * p0210) Bit 5: Line undervoltage (limit value 20 % * p0210) Bit 7: Peak current fault Bit 8: Smart Mode without VSM (p3400.5 = 0): Line angle deviation Bit 9: Smart Mode: DC link voltage dip Bit 10: Smart Mode: Line currents not symmetrical Remedy: Generally, the following applie s when an alarm message is output: - check the line supply and fuses. - check the line supply quality and system fault level. - check the load. Dependent on the alarm value in r2124, the following applies: Bit 0 = 1: Line fault occurred or poor/incorrect cont roller setting. For poor line quality or frequent line supply changeover operations, when required, limit value p3463 can be increased until the alarm value no longer occurs. Bit 2 = 1: Line fault occurred or poor/incorrect cont roller setting. - check t he controller setting and load. Bit 3 = 1: Line fault occurred. For poor line q uality or frequent line changeover operations, when required, limit values p0284 and p0285 can be incr eased until the alarm value no longer occurs. Bit 4 = 1: Line interrupted or line overvoltage has occurred. Bit 5 = 1: Line interrupted or line undervoltage has occurred. Bit 7 = 1: Peak current trip due to li ne fault or overload. Check the load. Bit 8 = 1: Line fault occurred. Bit 9 = 1: Line undervoltage or overload. Check the load. Bit 10 = 1: Line supply interrupted in at least one line phase. Check the fuses. See also: r3405 (Status word infeed), p3463 (Inf eed, line angle change, phase failure detection)
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 206205 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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