Siemens alarm 400203: DB acces error: DB%Z
SINUMERIK PLC system alarm · Siemens 840D/810D powerline
What it means
Access to the data block named in %Z failed because the DB is missing entirely, is write-protected, or is too small for the data being written. Unlike 400201 this is not about loading during RUN but about the DB's presence, protection status or length at access time. The named block has to be restored via STEP 7 before operation can continue.
Likely causes
- Data block deleted from the PLC project or never loaded
- DB write protection set in the CPU or source
- DB created shorter than required by the basic program interface
Triage note: Text reproduced as printed in the 06/2019 manual ('acces'). Program continuation: switch control OFF - ON.
Need the part urgently?
Send us alarm 400203 with your machine details — typical RFQ turnaround is 24–48h.