Siemens SINAMICS S120 Function Manual page 234

Vector control
4.20 Flying restart
Flying restart in encoderless operation for long cables
As a rule, it is important to consider the cable resistance. The cable resistance is required for
calculation of the thermal motor model.
1. Enter the cable resistance in parameter p0352 before you carry out motor identification.
2. Set parameter p1203[0...n] to at least 300%.
Note
Use a trace recording to check and optimize the flying restart function. If necessary, optimize
the settings of parameters p1202 and p1203.
Fast flying restart
For encoderless operation (vector, V/f linear and parabolic), there is a "fast flying restart".
For fast flying restart, the starting frequency is set to zero. The model settles within
approximately 200 ms on its own when the parameterization is correct. Fast flying restart
works only under the following conditions:
● At a current controller cycle time of 250 μs or 400 μs (without filter and long cables)
● Up to 4x the rated speed for vector control
● Up to the rated speed for V/f control
Note
The "fast flying restart" function is only possible for induction motors.
232
This operation can take a little longer than for the factory setting (100%).
Function Manual, (FH1), 01/2013, 6SL3097-4AB00-0BP3
Drive functions