Position Controller - Siemens SINUMERIK 840Di Manual

10 NC Start-Up with HMI Advanced
10.5 Axes and spindles

10.5.14 Position controller

Closed-loop
control circuits
SINUMERIK 840Di
Setpoint position
from
Position
interpolator
controller
Actual position
Fig. 10-18 Closed-loop control circuits
Traversing
direction
Control direction
Loop gain
10-332
The closed-loop control of a machine consists of the cascaded closed-loop
control circuits of current controller, speed controller and position controller.
PROFIBUS DP drive
Speed
n
set
controller
n
act
Actual speed value
If the axis does not traverse into the desired direction, the appropriate
adaptation is made in
S
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
S
MD32110: ENC_FEEDBACK_POL (sign of actual value).
In order to obtain high contour accuracy, a high loop gain (K
position controller is required. However, an excessively high K
overshoot, instability and impermissibly high machine loads.
The maximum permissible K
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.
Current
i
set
controller
i
act
Actual current value
factor is dependent on the dynamic response of
V
 Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
06.03
Encoder
Motor
factor) of the
V
factor causes
V