ARTDrive V2 series - Instruction Manual Chapter 7 Appendix • 335
diameter, in order to send to the Drive the right value of the angular speed.
NOTE! When PID MltPI selmon = 0 and the PI Block is disabled, the system
keeps into memory the last calculated value of PID out mon. In case
the machine is switched off, such value is automatically reset. In case
the value of this parameter has to be set in order to have on the
output a wrong reference equal to the feed-forward, it is possible to
configure a digital input as a correction reset.
It is therefore necessary to:
select Mlt PI sel 0 = DI 4 monitor
set PID Mlt PI sel 1 = 1
By bringing the digital input to a high logic level, the value of PID out mon is
set at 1.
Set PI lim top and PI lim bot according to the winder diameter ratio.
The PI lim top and PI lim bot parameters can be considered, respectively,
as a maximum and minimum multiplicative factor of the feed-forward.
Considering that the motor angular speed, and therefore the reference, are
inversely proportional to the winding/unwinding diameter, set:
PI lim top = 1
PI lim bot = Φmin / Φmax = 100 / 700 = 0.14
Here following is a description of the above statements.
Calculation of the motor angular speed:
ω max. = Vl / (Φ x Φmin x R)
and
ω min = Vl / (Φ x Φmax. x R)
where:
ω max. = motor angular speed with a minimum diameter [rpm]
ω min = motor angular speed with a maximum diameter [rpm]
Vl = line speed
Φmin = winder minimum diameter [m]
Φmax. = winder maximum diameter [m]
R = motor-winder reduction ratio
Therefore: ω max. / ω min = Φmax. / Φmin
where
ω min = (Φmin / Φmax) x ω max.
Consider that the PI lim top and PI lim bot parameters can be considered,
respectively, as a maximum and minimum multiplicative factor of the feed-
forward.
Multiply the feed-forward by PI lim top = 1, the result is the maximum speed
reference referring to the minimum diameter.
Multiply the feed-forward by PI lim bot = 0.14, the result is the minimum
speed reference referring to the maximum diameter.
Such application requires a proportional-integral regulation on the side of the
system.
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