Lenze 8615E - Manual (Page 77)

75
Closed-loop control without pilot control, closed-loop control
of an application datum
The PI controller is normally used for the speed control of the
connected motor. The large setting ranges of the control
parameters also allow the control of an application datum if this
depends on the drive speed. For this it may be necessary to switch
off the frequency pilot control and to set the PI controller to 100%
influence.
The feedback gain and the control parameters must be adjusted
according to the corresponding conditions.
Code Parameter Meaning Acceptance
C074 0.0%
˝0.0...100% Influence of the PI controller ON-LINE
C238 -0-
-1-
-2- No pilot control
With set-value pilot control
With feeback pilot control [SH + PRG]
4.4 Adjustment of the feedback gain
If you use an incremental encoder for speed control and you have
entered the encoder constant as described under 4.2. (see page
61) an adjustment of the feedback gain is not necessary. For
tacho feedback, a gain adjustment is normally required.
4.4.1 Automatic adjustment
To adjust the feedback gain you can activate an automatic adjustment
under C029. Proceed as follows:
•
Activate the closed-loop speed control (C005) with pilot control
of the output frequency by the controller reference
(C238 = -1-).
•
Set the influence of the PI controller to zero under C074.
•
Idle running. If this should not be possible, please note that the
slip of the machine is added as gain error during the automatic
adjustment. If necessary, set manually.
•
If possible, enter 100% set-value. If the set-value is smaller than
10% an auto-adjustment is not possible.
•
Enable the controller and wait for the acceleration.
Activate the auto-adjustment via C029 using SH + PRG.
•
If the auto-adjustment was successful, "--ok--" appears on the
display. If not, please check your settings. With the acceptance
of the auto-adjustment the feedback gain is set under C027.
•
Set under C074 the influence of the PI controller such that the
slip occuring during operation can be controlled.
To set the adjustment time and the gain of the PI controller see
page 76.