Siemens alarm 611-IR-LEDS-dark: Infeed module shows no LED at all although 3x400 V present (or red LED after X351 restart)
SIMODRIVE 611 I/R module LED indication (6SN1145/6SN1146) · SIMODRIVE 611D/611U
What it means
Either low-voltage converter dead, or the infeed refuses to switch on the 600 V bus because it detects a short circuit on the DC link or on the X351 electronics-power distribution.
Likely causes
- short circuit on 600 V bus - most frequently a failed spindle power module (6SN1123/6SN1146-based AM)
- short in low-voltage section via X351 ribbon (one drive's plug-in control board loading the rail)
- failed low-voltage converter inside infeed itself
- red LED clearing after unplugging X351 = one drive's regulator plug-in module at fault
Triage note: Isolation procedure: loosen DC-link screws / unplug X351 per module starting from right-hand end until symptom clears - last-disconnected module is the culprit. If unsure whether power module or control board, send pair together for test.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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6SN1123-… (spindle sizes 50A/80A/160A most common)
spindle power module shorting DC bus · Primary suspect
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6SN1118-…
regulator/control plug-in board (X351 rail short) · Common cause
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6SN1145-… / 6SN1146-…
infeed module (if isolated from all drives and still dead) · Common cause
Need the part urgently?
Send us alarm 611-IR-LEDS-dark with your machine details — typical RFQ turnaround is 24–48h.