PLCS7-1200Verified · sol.ls-electric.com
S7-1200 LED-PWR-OFF — PWR LED off
Critical — power cycle required
CAUSE
Why does it occur?
No 24V supply to the CPU — possible SMPS output, input terminal, or blown fuse.
REMEDY · Step by step
How to fix it?
Measure 24V at the power supply, verify SMPS output, check L+/M wiring, and replace the fuse.
Do not reset repeatedly before identifying the cause. Repeated resets while ignoring a trip/alarm can cause secondary damage (IGBT failure, motor winding damage, etc.).
SOURCE
Related manual page
Summary based on the official Siemens AG manual. For accurate and complete information, always consult the official manual.
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