Mitsubishi Electric Freqrol-A100 Instruction Manual page 155

4.8 PI CONTOROL. FUNCTION
cess control can be exercised for flow rate, air volume: pressure, etc.
1
L '
Pro
by the inverter.
L
4.8.1
Operation
(1) PI control system configuration
Manin,
,-
. . . .
-
. .
-
.
Set value u
drive
circuit
Kp: Proportional constant Ti: Integral time S: Operator
(2) Overview of PI control action
1) PI control action
[Example of operation performed when process
PI control action is a combination of proportional
value varies step by step]
(P) control action and integral (I) control action de-
signed to provide a manipulated value according
Deviation Set value
to an error and a change with time.
action
I control
_ / I
action
,
,.?
8
. $
t
2) Reverse action
3)
Forward action
Note: PI control action is combined P and I control
The manipulated value (output frequency) is increased when deviation
X (set value
-
process value) is positive, and is decreased when the
deviation is negative.
Set value
[Heating]
set value
Cold-tfi increased
Hot +fi decreased Process value
-
I
process value
\
Positive deviation
The manipulated value (output frequency) is increased when deviation
X (set value
-
process value) is negative, and is decreased when the
deviation is positive.
[Cooling] Negative deviation
Too cold+fi decreased Process value
set value
y-yT
Hot +fi increased
process value