Siemens alarm 400902: Parameter ChanNo impermissible in FC9
SINUMERIK PLC system alarm · Siemens 840D/810D powerline
What it means
The standard block FC9 was called with a channel number that does not exist in this control configuration. Siemens' auxiliary function blocks validate their parameters at runtime and reject impossible channel references with this alarm. The call parameter in the user/basic program must be corrected; the control then requires OFF/ON.
Likely causes
- FC9 called with ChanNo beyond configured channel count
- Channel deleted/renumbered without updating PLC calls
- Hardcoded parameter from another machine copied into this project
Triage note: Family entry: the FC parameter-check alarms 400902-402602 all read 'parameterized ... does not exist' - e.g. 401502/401602/401805 (axis in FC15/16/18), 401702 (spindle IF in FC17), 401901/402401/402501/402601 (mode group BAGNo), 401902/402402/402502/402602 (ChanNo), plus 400903 (interrupt IntNo in FC9) and 411101 (axis in FB11).
Need the part urgently?
Send us alarm 400902 with your machine details — typical RFQ turnaround is 24–48h.