Siemens SINAMICS S120 Commissioning Manual page 310

Diagnostics
3.5 Fault and alarm messages
Explanations of the alarm classes
● Alarm class A: Drive operation currently not limited
● Alarm class B: Time-limited operation
● Alarm class C: Functionally limited operation
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– e.g. alarm when measurement systems inactive
– no limitation on current movement
– Prevent possible switching to the defective measuring system
– e.g. prewarning temperature: without further action the drive may need to be switched
off
– After a timer stage -> additional fault
– after exceeding a switch-off threshold -> additional fault
– e.g. reduced voltage/current/torque/speed limits (i2t)
– e.g. continue with reduced accuracy / resolution
– e.g. continue without encoder
Commissioning Manual, (IH1), 01/2013, 6SL3097-4AF00-0BP3
Commissioning Manual