GE Industrial Solutions DV-300 DC Drive Users Manual - Manual (Page 274)

GEI-100332Ga
——— FUNCTION DESCRIPTION ———
6
146
PI integral freeze Freezing of the present condition of regulator integral component.
PI output PID Output of PI block, adapted to the values included between PI top limit and PI bottom
limit. At the power up of the drive, PI output PID acquires automatically the selected
value with PI central v sel multiplied by 1000.
Example: If PI central v 2 = 0.5 is selected, at the start PI output PID acquires value = 500.
When Enable PI PID has been enabled, the output PI output PID is, independently on the input error able to
integrate its value up to the limits set with PI top limit or PI bottom limit multiplied by 1000.
Example: PI top limit = 2, PI output PID max = 2000.
The PI block output will be further limited from the parameter saturation Real FF PID (see corresponding parameter).
As previously described, PI output PID is used as a multiplier factor of the feed-forward in order to obtain the angular
speed reference of the motor. If the PID function is used to control a winder/ unwinder system, its value is inversely
proportional to the roll diameter. When winding with a constant peripheral speed, the following is valid:
ω
0
Φ
1
=ω
1
Φ
1
where:
ω
0
= angular speed at minimum diameter
Φ
0
= minimum diameter
ω
1
= angular speed at actual diameter
Φ
0
= actual diameter
ω
1
= ω
0
x (Φ
0
/Φ
1
)
If the drive is set correctly, and ω
0
is equivalent to the maximum value of the feed-forward, then PI output PID
depends on (Φ
0
/Φ
1
).
Taking into consideration the internal coefficients of the firmware, it can be written:
PI output PID = (Φ
0
/Φ
1
) x 1000
This formula can be used to verify the accuracy of the setting when the system is on working or during the
procedure for the calculation of the initial diameter.
Real FF PID
Represents the feed-forward value which has been recalculated according to the PI cor-
rection. It will be calculated with the following formula:
Real FF PID = (Feed-fwd PID / 1000 ) x PI output PID
The max. value of Real FF PID is +/- 10.000.If this limit had been reached during operation, in order to avoid
dangerous levels of regulator saturation, further increases of PI output PID will be blocked.
Example: Feed-fwd = + 8000, the positive limit of PI output PID will be automatically set at
10000 / ( 8000 / 1000 ) = 1250.