Siemens SINAMICS S150 NEMA, Operating Instructions Manual

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Setpoint channel and closed-loop control
7.4 Vector speed/torque control with/without an encoder
Enclosed Drives
Operating Instructions, 12/2018, A5E36652151A
479
7.4.4.6 Open actual speed value
Description
Via parameter p1440 (CI: speed controller, speed actual value) is the signal source for the
speed actual value of the speed controller. The unsmoothed actual speed value r0063[0] has
been preset as the signal source in the factory.
Depending on the machine, parameter p1440 can be used, for example, to switch on a filter
in the actual value channel or feed in an external actual speed value.
Parameter r1443 displays the actual speed value available at p1440.
Note
Feed in an external actual speed value
When infeeding an external actual speed value, care should be taken that the monitoring
functions continue to be derived from the motor model.
Response for speed control with an encoder (p1300 = 21)
A motor encoder must always be available for the speed or position signal of the motor
model (e.g. evaluation via SMC, see p0400). The actual speed of the motor (r0061) and the
position information for synchronous motors still come from this motor encoder and are not
influenced by the setting in p1440.
Interconnection of p1440:
When interconnecting connector input p1440 with an external actual speed value, ensure the
speed scaling is the same (p2000).
The external speed signal should correspond to the average speed of the motor encoder
(r0061).
Response for speed control without an encoder (p1300 = 20)
Depending on the transmission path of the external speed signal, dead times will
accumulate; these dead times must be taken into account in the speed controller's
parameter assignment (p1470, p1472) and can lead to commensurate losses in dynamic
performance.
Signal transmission times must therefore be minimized.
P1750.2 = 1 should be set so that the speed controller is also able to operate at standstill
(closed-loop controlled operation to zero frequency for passive loads). Otherwise, at low
speeds it switches over to speed-controlled operation, so that the speed controller is
switched off and the measured actual speed no longer has an influence.