Siemens alarm 400253: PLC STOP because of SPL system error
SINUMERIK PLC system alarm · Siemens 840D/810D powerline
What it means
The cross-check of SPL data between NCK and PLC was interrupted, and five seconds later the PLC was deliberately driven to STOP. SPL is the safety-relevant data linkage used with Safety Integrated, so losing its consistency is treated as a stop-worthy condition rather than a warning. The system must no longer start SPL until the PLC carries the correct FB15 version and DB18.
Likely causes
- Mismatched or outdated FB15 / DB18 relative to the loaded basic program
- Communication interruption between NCK and PLC during SPL operation
- Attempted SPL start with inconsistent Safety Integrated versions
Triage note: Official remedy includes 'do no longer start SPL' and verifying FB15/DB18; related version alarms are 411501/411502.
Need the part urgently?
Send us alarm 400253 with your machine details — typical RFQ turnaround is 24–48h.