Open Actual Speed Value - Siemens SINAMICS S120 Function Manual

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Vector control

6.6 Open actual speed value

Open actual speed value

Function description

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, 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.

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

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.

Function Manual, 06/2019, 6SL3097-5AB00-0BP2

Drive functions