InverterSINAMICS V20Verified · sol.ls-electric.com
SINAMICS V20 F71 — USS fieldbus timeout
Alarm — operational, inspection needed· AUTO-RESET
CAUSE
Why does it occur?
BOP/USS communication lost — cable fault or upstream master down.
REMEDY · Step by step
How to fix it?
Check the RS-485 wiring and termination resistor, and check the master polling cycle.
Do not reset repeatedly before identifying the cause. Repeated resets while ignoring a trip/alarm can cause secondary damage (IGBT failure, motor winding damage, etc.).
SOURCE
Related manual page
Summary based on the official Siemens AG manual. For accurate and complete information, always consult the official manual.
Open official manual ↗CALLBACK