Open Actual Speed Value - Siemens SINAMICS S120 Function Manual

Vector control

5.7 Open actual speed value

5.7 Open actual speed value
Via the parameter p1440 (CI: Speed controller actual speed value) is the signal source for
the actual speed value of the speed controller. In the factory setting, the unsmoothed actual
speed value r0063[0] is the default signal source.
Via parameter p1440, for example, a filter can be switched into the actual value channel or
an external actual speed value can be fed in, according to the specific system requirements.
Parameter r1443 displays the actual speed value present at p1440.
Note
When feeding in an external actual speed value, ensure the monitoring functions continue to
be derived from the motor model.
Behavior 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).
Behavior for speed control without an encoder (p1300 = 20)
Depending on the transmission path of the external speed signal, dead times will occur;
these dead times must be taken into account in the speed controller's parameter assignment
(p1470, p1472) and can lead to corresponding losses in the dynamic performance.
Signal transmission times must therefore be minimized.
p1750.2 = 1 should be set so that the speed controller is also able to work 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.
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Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Drive functions