67
increase Safe_Dist(3040.06) to get more precise results. If the machine shakes too much, reduce_Safe_Dist
to reduce oscillation.
7.1.3 Problems with auto-tuning
If the tuning process has failed, the error result of tn03 / Inertia_Get_Result(3040.09) tells the fail-reason:
0:
The controller could not be enabled by any reason.
-1:
Inertia cannot be measured due to too little motion or too little current.
-2:
The measured inertia result is outside the valid range.
-3:
The resulting Inertia_Ratio value is greater than 250 (inertia ratio > 25). This is a possible result,
but the control loop will not be tuned.
-4:
The resulting Inertia_Ratio value is larger than 500 (inertia ratio > 50). This is an uncertain result.
In the cases 0, -1, -2, -4 Inertia_Ratio is set to 30, in the case -3 Inertia_Ratio is set as measured, Stiffness
is set to 7-10
In any fail case the control loop parameters are set to Inertia_Ratio of 30 and the set Stiffness values. To
make the measured Inertia_Ratio of case -3 become effective, the value of tn02 must be confirmed by SET
or the Inertia_Ratio(3040.0
B) must be written once.
Information
Reasons for the failure of auto-tuning:
Incorrect wiring of the CMMB servo system
DIN function Pre_Enable is configured but not active
Too much friction or external force is applied to the axis to be tuned
Too big backlash in the mechanical path between the motor and the load
Inertia ratio is too large
The mechanical path contains too soft components (soft belts or couplings)
If none of those reasons can be encountered, Safe_Dist may be increased in order to remedy problems. If
auto-tuning still fails, manual tuning (see chapter 7.2) is adviced to be executed.
7.1.4 Adjustment after auto-tuning.
After auto-tuning the stiffness is set to a value in the range of 4 to 12. The greater the inertia ratio, the
smaller the stiffness value will be.
Table 7-2: Stiffness and control loop settings
Stiffness
Kpp/[0.01Hz]
Kvp/[0.1Hz]
Output filter
[Hz]
Stiffness
Kpp/[0.01Hz] Kvp/[0.1Hz]
Output filter
[Hz]
0
70
25
18
16
1945
700
464
1
98
35
24
17
2223
800
568
2
139
50
35
18
2500
900
568
3
195
70
49
19
2778
1000
733
4
264
95
66
20
3334
1200
733
5
334
120
83
21
3889
1400
1032
6
389
140
100
22
4723
1700
1032
7
473
170
118
23
5556
2000
1765
8
556
200
146
24
6389
2300
1765
