Siemens alarm 611-IR-LED4-yellow-dark: Infeed/monitoring module LED 4 (yellow) dark: DC link not charged - pulses cancelled for the drive group
SIMODRIVE 611 I/R module LED indication (6SN1145/6SN1146) · SIMODRIVE 611D/611U
What it means
Yellow lit is the healthy 'unit ready, DC link pre-charged' state; yellow staying dark while other LEDs show supply health means the precharge sequence never completes and group pulses remain inhibited. Per Siemens the overvoltage limiter module must be checked whenever the yellow LED is dark or a line fault is shown.
Likely causes
- terminal 48 main-contactor command missing or feedback loop open
- precharge contactor/coils worn (NS1-NS2 chain never closes)
- defective overvoltage limiter module blocking the sequence
- excessive restart frequency triggering the infeed's thermal lockout (all LEDs dark until cooled)
Triage note: Siemens isolation procedure: power down, remove the overvoltage limiter, insert jumper X181 directly on the NE module - if the NE module now works, replace the limiter.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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overvoltage limiter module 6SN1112-… (where fitted)
infeed · Common cause
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main/precharge contactor
infeed · Common cause
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6SN1145-… / 6SN1146-…
infeed · Check if others ruled out
Need the part urgently?
Send us alarm 611-IR-LED4-yellow-dark with your machine details — typical RFQ turnaround is 24–48h.