Siemens SINUMERIK 840D Description Of Functions page 73

02.99
Optimization of
controller P
component
Optimization of
controller D
component
 Siemens AG 2000. All rights reserved
SINUMERIK 840D/SIMODRIVE 611 digital Descr. of Functions HLA Module (FBHLA) – 04.00 Edition
Relevant machine data:
MD 5406: SPEEDCTRL_GAIN_A (P gain of velocity controller A)
MD 5407: SPEEDCTRL_GAIN
MD 5408: SPEEDCTRL_GAIN_B (P gain of velocity controller B)
The theoretical characteristic data of the valve and cylinder are used to calcu-
late a suggested P gain value. The positive feedback area (MD 5406...MD 5408
<0) is included in the calculation to damp the drive system.
The adjustment to real conditions on the machine (special damping require-
ments) should be made according to the following criteria:
1. P component must be as positive as possible.
Optimization direction
< 0
2. The acceptable overshoot behavior represents the upper limit for the setting.
Note
P<0 (positive feedback) may be necessary to achieve the required damping
behavior. However, this setting will degrade the control quality. Friction in partic-
ular causes prolonged settling times.
Threshold values (typical):
S
f P>0


S
f P<0, or around zero

S
f P>0

(f ...f see Section 3.9.5 paras. 1...3)


Note
The P gain is specified as a percentage of MD 5435: CONTROLLED_SYS-
TEM_GAIN. P=–100% compensates the feedforward control.
Relevant machine data:
MD 5431: SPEEDCTRL_DIFF_TIME_A (Lead time T
MD 5432: SPEEDCTRL_DIFF_TIME
MD 5433: SPEEDCTRL_DIFF_TIME_B (Lead time T
MD 5430: SPEEDCTRL_PT1_TIME (velocity controller smoothing time
constant)
The positive phase displacement of the derivative term can be utilized to ac-
tively dampen the controlled system for f
The derivative-action time constant/corner frequency must be parameterized to
values higher than the minimum natural frequency of valve and drive.
3.9 Fine adjustment and optimization
(P gain of velocity controller)
MD 5406
MD 5407
MD 5408
0 > 0
(Lead time T
type.

3 Start-Up
of velocity controller A)
V
of velocity controller)
V
of velocity controller B)
V
3-73