Omron SYSDRIVE MX2 SERIES User Manual page 190

5-6 Operation Functions
Basic Structure of PID Control
Deviation ε
Target value
+
−
0 to 10 V
4 to 20 mA
PID Operation
(1) P operation
Operation where the manipulated value is proportional to the deviation (target value − current
value).
Target value
Manipulated value
5
(2) I operation
Operation where the mainpulated value is proportional to the time-integrated value of
deviations. As the current value becomes closer to the target value, the deviation decreases
and thus the effect of P operation is reduced, and consequently the time needed to achieve
the target value increases. I operation compensates for this condition.
Target value
Manipulated value
(3) D operation
Operation where the mainpulated value is proportional to the ratio of change in deviation.
Although use of PI operations alone require a response time, D operation has the effect of
compensating for the response.
Target value
Manipulated value
5-75
Feedforward
1
+
Kp 1 Td · s
+ +
Ti · s
+
Feedback 0 to 10 V
4 to 20 mA
Kp: Proportional gain
Changes in steps
Large
A072
Small
Small
A073
Large
Large
A074
Small
Disabled
0 to 10 V
4 to 20 mA
Manipulated
Normal control
value
of the Inverter
fs
Ti: Integral time Td: Differential time
Changes in lamps
Large
A072
Small
Small
A073
Small
Large
A074
Small
SYSDRIVE MX2 Series USER'S MANUAL (3G3MX2-Axxxx)
Sensor
=
M
Transducer
ε: Deviation
s: Operator