Sinumerik Alarm 300200 Drive bus hardware fault

Sinumerik Alarm 300200 Drive bus hardware fault

The drive bus has a fault. The following causes are possible:
• The bus terminator is missing.
• The drive bus is physically interrupted at some point.
• Miscellaneous hardware fault. A check line is tested that runs over the entire bus and returns from the last rack location (bus terminator) back to the NCK. Note: If the drive ramps up correctly even though this message appeared, the error existed only at the beginning of the initialization. In spite of this, the drives can be capable of functioning.

– Mode group not ready.
– Channel not ready.
– NC Start disable in this channel.
– The NC switches to follow-up mode.
– Alarm display.
– Interface signals are set.

Please inform the authorized personnel/service department.
– Check the bus terminator.
– Check all plug connections from the drive bus to the drive modules.
– Other hardware faults. If the remedial measures given above do not lead to a change in the behaviour when starting, please contact the system support for the A&D MC products of SIEMENS AG through the Hotline (tel.: see alarm 1000).

Program Continuation:
Switch control OFF – ON.


  1. Siemens Diagnostics Guide by Siemens
Sinumerik Alarm 300200 Drive bus hardware fault