GE AV-300i, User Manual, Page: 159 / 296

AV-300i Version 2 User’s Guide
—————— Function Description ——————
Ch.1
159
Set:
PID Mlt PI sel 1 = 1 The starting value is 1
Without a correction performed by the regulator PI Block, the line speed reference (Feed-Forward) must be
multiplied by 1 and must be sent directly to the Drive speed regulator. The regulator usually carries out a
Proportional-Integral control. The correction is stated as a percentage of the line speed, from 0 to the maximum
value.
Set :
PI lim top and PI lim bot in order to obtain a maximum correction of the PI Block equal to 20% of the line speed.
The PI lim top and PI lim bot parameters can be considered, respectively, as the maximum and minimum
multiplicative factor of the feed-forward.
2550rpm of the motor (max. feed-forward) correspond to the max. line speed.
Maximum correction = 2550 x 20% = 510rpm
2550 + 510 = 3060rpm ——> PI lim top = 3060 / 2550 = 1.2
2550 - 510 = 2040rpm ——> PI lim bot = 2040 / 2550 = 0.80
With such a configuration and with a proportional correction of the line speed, the PI block is not in a position
to carry out the initial phase when the machine is stopped; it is therefore necessary to act also on the PD Block.
The gains of the different components have to be set, experimentally, with a loaded machine; such tests can be
started with the values stated below (default values):
Set PI P1 gain % = 2%
Set PI I1 gain % = 2%
Set PD P1 gain % = 1%
Use the derivative component as a system “damping” element, by setting for example:
PD D1 gain % = 1%
PD der filter = 20ms
If it is not required, leave these parameters = 0.
In case a series of cascade references has to be performed for another possible Drive, set PID out mon on an
analog output, for example:
An out 1 src = PID out mon
N
OTE
!
See the “Generic PID” paragraph in case it is necessary to have a system with an integral
regulation enabled also with feed-forward = 0 and in a position to carry out the system initial
phase without errors even with a stopped machine.