Siemens MICROMASTER 440 Operating Instructions Manual page 52

6 Commissioning
Control word of motor model
P1750 = ...
This parameter controls the operation of the sensorless vector control (SLVC) at very low
frequencies. This therefore includes the following conditions:
Bit00 Start SLVC open loop
(Operation directly after an ON command)
Bit01 Zero crossing SLVC open loop
(zero crossing)
f
p1755
For most applications the setting of parameter p1750 = 0 gives the best result at low
frequency.
Start-freq. motor model (SLVC)
P1755 = ...
Enter the start frequency of sensorless vector control (SLVC), thereby SLVC switches over
from open-loop to closed-loop at that frequency.
r0062
Frequency
setpoint
p1452
52
Start
Closed loop
Open loop
t
Pre-
control
Speed
controller
−
p1470 p1472
Flux setpoint
closed loop
p1610
Flux setpoint
p1611
open loop
+
Act. frequency
−
Slip
Observer model
closed loop
0 NO 1 YES
0 NO 1 YES
Zero crossing
f
Closed loop
p1755
Open loop
p1755
Torque
limitation
i
. sq
.
p1750/p1755
open/closed
Current
loop
controller
i
sd
Current
measurement
+
0
Operating Instructions (Compact)
Issue 10/06
1
t
5.0 Hz
Act. output
voltage
i
u
i
v
i
w
Act. angle
Act. output
frequency
MICROMASTER 440