Siemens SINAMICS S120 Function Manual page 81

Formula to calculate the cable resistance:
R (cable resistance) +
= 0.0178 W
r
copper
I = Cable length [m]
A = Cable cross-section [mm
The motor should be at room temperature when the identification routine is carried-
out. The compensation of the voltage emulation error must be activated (p1780.8
= 1).
A KTY sensor (p0601 = 2 or 3) should be used to sense the motor temperature
(p0600).
The estimator requires the motor temperature in order to track/correct the tempe-
rature-dependent quantities. If a motor temperature sensor is not connected, then
the accuracy is significantly restricted.
The k estimator is only activated above a specific speed (p1752). The terminal
T
voltage of the drive converter always has small errors, caused by voltage drives
across the power semiconductors etc. The lower the speed and therefore the out-
put voltage, the greater the negative influence on the estimation as a result of low
voltage errors. This is the reason that the estimation is de-activated below a speci-
fic speed. The estimated value is smoothed using time constant p1795. The cor-
rection value for the torque constant is displayed in r1797. By identifying the torque
constant k
be improved also below the speed threshold (1752).
The k estimator is activated using p1780.3 and the voltage compensation using
T
p1780.8.
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition
r (specific resistance)
mm
2
m
2
]
using the rotating motor identification routine, the torque accuracy can
T
l (cable length)
A (cross section)
Operating Modes
Servo control
3-81