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Siemens SINUMERIK Controller
PLC · Intermediate · 30-120 minutes
Siemens 840D 400177 - Delete DB 77 in the PLC and restart
This alarm occurs when the size of DB 77 in the PLC differs from the one created by the basic program. Fix it by deleting DB 77 in the PLC and restarting the system.
400177
Siemens 840D 400177 - Delete DB 77 in the PLC and restart
Delete DB 77 in the PLC and restart
Siemens SINAMICS drive alarm 400177: Delete DB 77 in the PLC and restart. This alarm indicates a fault condition in the SINAMICS servo drive system. Refer to the Siemens SINAMICS fault list documentation for the complete remedy.
Root Cause Summary
This alarm occurs when the size of DB 77 in the PLC differs from the one created by the basic program. Fix it by deleting DB 77 in the PLC and restarting the system.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Access PLC data
Navigate to the PLC data blocks in the Siemens control system.
- 2
Delete DB 77
Locate and delete DB 77 from the PLC memory.
- 3
Restart system
Perform a system restart to regenerate DB 77 with the correct size.
Call a technician if:
- ·If the alarm persists after deleting DB 77 and restarting
- ·If DB 77 cannot be deleted due to access restrictions
Prevention
- Avoid manual edits to PLC data blocks without documentation
- Ensure program updates are tested in simulation mode first
Common Mistakes
- Attempting repair without proper lockout/tagout procedures
- Not creating a backup before deleting data blocks
- Restarting without deleting DB 77
- Deleting the wrong data block
- Proceeding without proper PLC programming knowledge
Seeing Multiple Alarms?
Seeing another alarm with this one? Enter the code.
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