AV-300i Version 2 User’s Guide
—————— Function Description ——————
Ch.1
149
1.15.4.1 Setting of the Starting Diameter
By selecting PID MltPI sel mon = 0, when the PI Block is disabled (PID PI enab = 0), the last value of the
calculated integral component is kept into memory. Such integral component is displayed in PID PI out mon (it
corresponds to the winder diameter). When the Block is enabled again, the regulation starts from the calculated
value. The same function is foreseen also in case the Drive stops.
This operative method can be used, when, by controlling, for example, a winder, it is necessary to stop the
machine, to disable the Drive or to disconnect the switchboard.
By selecting PID MltPI selmon = 1-2-3, when the PI Block is disabled, the value of the PID PI out mon output
is the same as the one of the set parameter. When the Drive is stopped and then started again, the previously
stated value is automatically reset
only if , during the power supply, the digital input, set as Enable PI PID, is
already at a high level.
1.15.4.2 Gain Increase at the Starting
When PID FF mon is lower than PI steady thr, the integral regulation is frozen and the proportional gain gets
the value set in PI P init gain.
When PID FF mon overcomes the threshold, the integral regulation is enabled with the gain set in PI I init gain.
The PI Block keeps the PI P init gain and PI I init gain gains for the time set via PI steady delay. After this
time, the gain values are brought respectively to those generated by the gain adaptive.
1.15.4.3 PI Clamp Top and Bottom Setting
As previously stated, PID PI out mon is used as a multiplicative factor of the feed-forward in order to obtain
the motor angular speed reference; in case the PID function is used to control a winder/unwinder, its value is
inversely proportional to the winder diameter.
By winding with a constant peripheral speed, it is possible to write that:
ωω
ωω
ω
0
ΦΦ
ΦΦ
Φ
0
=
ωω
ωω
ω
1
ΦΦ
ΦΦ
Φ
1
where:
ωω
ωω
ω
0
= angular speed with a minimum diameter
ΦΦ
ΦΦ
Φ
0
= minimum diameter
ωω
ωω
ω
1
= angular speed with the present diameter
ΦΦ
ΦΦ
Φ
1
= present diameter
w
1
= w
0
x (
ΦΦ
ΦΦ
Φ
0
/
ΦΦ
ΦΦ
Φ
1
)
By tuning the Drive properly,
ω ω
ω ω
ω
0
corresponds to a wrong feed-forward, therefore PID PI out mon depends on
(
ΦΦ
ΦΦ
Φ
0
/
ΦΦ
ΦΦ
Φ
1
).
It is possible to write that: PID PI out mon = (
ΦΦ
ΦΦ
Φ
0
/
ΦΦ
ΦΦ
Φ
1
)
This formula can be used to check the right tuning execution when the system is active or during the procedure
for the calculation of the starting diameter.
1.15.5 Proportional Derivative Control (PD Control)
This Block performs the Proportional Derivative regulation.
The PD Block has on the input the PID Input value (output value of the PID Input Block), which usually states
an error. The output of the Block is added to the other corrections in the PID output Block.
The PID PD enab src
source allows to enable the PD function.
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