Detailed Description
2.5 Optimization of the control
Velocities, Setpoint/Actual-Value Systems, Closed-Loop Control (G2)
2-72 Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
MD32210 $MA_POSCTRL_INTEGR_TIME ; integral time [sec.]
Effect of integral time:
– T
n
→ 0:
The control error is corrected quickly; however, the control loop can become instable.
– T
n
→ ∞:
The control error is corrected more slowly.
4. Find the appropriate compromise for T
n
for your application, using these two extreme
cases as outer limits.
T
n
must not be set too close to the instability limit, since there is a risk of damage to the
machine if instability should occur.
5. Use servo trace to trace the travel-in of an automatic program traveling to and from a
target position.
6. Set the servo trace to display the following:
– Following error
– Actual velocity
– Actual position
– Reference position
7. Reset the tolerance values in the following machine data to the required values, once the
optimum value for T
n
has been identified:
– MD36020 $MA_POSITIONING_TIME
– MD36030 $MA_STANDSTILL_POS_TOL
– MD36040 $MA_STANDSTILL_DELAY_TIME
– MD36400 $MA_CONTOUR_TOL
Example
Setting result after several iterative processes for K
R
and T
n
.
Each of the following quantities - following error, actual velocity, actual position, and position
setpoint - has been recorded by servo trace. When traversing in JOG mode, the
characteristic of the individual data shown in the following figure was then drawn.
Set machine data:
MD32220 $MA_POSCTRL_INTEGR_ENABLE = 1
MD32210 $MA_POSCTRL_INTEGR_TIME = 0.003
MD32200 $MA_POSCTRL_GAIN[1] = 5.0
Parameter set selection 0
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