Siemens SINUMERIK 840Di, Руководство пользователя, Страница: 332 / 552

06.03
10.5 Axes and spindles
10-332

Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
10.5.14 Position controller
The closed-loop control of a machine consists of the cascaded closed-loop
control circuits of current controller, speed controller and position controller.
Position
controller
Speed
controller
i
set
n
set
Current
controller
n
act
i
act
Setpoint position
from
interpolator
Motor
Encoder
Actual position
SINUMERIK 840Di PROFIBUS DP drive
Actual speed value
Actual current value
Fig. 10-18 Closed-loop control circuits
If the axis does not traverse into the desired direction, the appropriate
adaptation is made in
MD32100: AX_MOTION_DIR (traversing direction).
The value “–1” reverses the direction of motion.
If the control direction of the position measuring system is incorrect, it can be
adjusted with
MD32110: ENC_FEEDBACK_POL (sign of actual value).
In order to obtain high contour accuracy, a high loop gain (K
V
factor) of the
position controller is required. However, an excessively high K
V
factor causes
overshoot, instability and impermissibly high machine loads.
The maximum permissible K
V
factor is dependent on the dynamic response of
the drive and the mechanical system of the machine.
If “0” is entered for the loop gain factor, the position controller will be discon-
nected.
Closed-loop
control circuits
Traversing
direction
Control direction
Loop gain
10 NC Start-Up with HMI Advanced