Code 380020: PROFIBUS/PROFINET: Bus %3 SDB %4 error %1 source %2
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical PROFIBUS/PROFINET: Bus %3 SDB %4 error %1 source %2 alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Parameters: %1 = Error %2 = SDB source %3 = Bus number %4 = SDB number Definitions: Error in SDB for configuring PROFIBUS/PROFINET. Causes of the error: - 01 = SDB does not exist in source. - 02 = SDB from source is too large. - 03 = SDB from source cannot be activated. - 04 = Source is empty. - 05 = Source is not present. SDB source: - 99 = Passive file system: _N_SDB_DIR - 100 = CF card: /siemens/sinumerik/sdb/... - 101 = CF card: /addon/sinumerik/sdb/... - 102 = CF card: /oem/sinumerik/sdb/... - 103 = CF card: /user/sinumerik/sdb/... Reaction: PROFIBUS/PROFINET is inacti ve or working with the default SDB. Reaction: Channel not ready. NC Start disable in this channel. Interface signals are set. Alarm display. Remedy: - Check the setting of MD 11240 $MN_PROFIBUS_SDB_NUMBER. - If source = 100: Check directory _N_S DB_DIR in the passive file system. - If source = 103-106: Check directories on CF card Program Continuation: Switch control OFF - ON.
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 380020 on the SINUMERIK 840D CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4014 Siemens SINUMERIK 840D CNC codes.
Have a better solution?
Help the industrial community by sharing your repair experience for code 380020.
Need a searchable reference for more Siemens SINUMERIK 840D CNC manuals?
We structure equipment manuals into searchable code, title, cause, solution, safety note, and source-reference data. Send a PDF and example searched codes when you need public pages, private search, or structured exports.
Space reserved for Google AdSense / Industrial Affiliate Links
Monetization target for 2026