Chapter 11 Description of Parameter Settings
|
C200 Series
11-111
08 High-function PID Parameters
This parameter can be set during operation.
Input Terminal for PID Feedback
Factory
Setting:0
Settings 0: No function
1: Negative PID feedback: input from external terminal AVI (Pr.03-00)
2: Reserved
3: Reserved
4: Positive PID feedback from external terminal AVI (Pr.03-00)
Negative feedback means: +target value – feedback. It is used for the detection value will be
increased by increasing the output frequency.
Positive feedback means: -target value + feedback. It is used for the detection value will be
decreased by increasing the output frequency.
Common applications for PID control
;
Flow control: A flow sensor is used to feedback the flow data and performs accurate flow
control.
;
Pressure control: A pressure sensor is used to feedback the pressure data and performs
precise pressure control.
;
Air volume control: An air volume sensor is used to feedback the air volume data to have
excellent air volume regulation.
;
Temperature control: A thermocouple or thermistor is used to feedback temperature data for
comfortable temperature control.
;
Speed control: A speed sensor or encoder is used to feedback motor shaft speed or input
another machines speed as a target value for closed loop speed control of master-slave
operation. Pr.10.00 sets the PID set point source (target value).
;
PID control operates with the feedback signal as set by Pr.10.01 either 0~+10V voltage or
4-20mA current.
PID control loop:
¨
S )
T
S
T
1
(1
K
d
i
p
×
+
×
+
IM
¿¥
+
-
Setpoint
drive execute PID control output value
feedback signal
sensor
p
K
: Proportional gain(P)
i
T
: Integral time(I)
d
T
: Derivative control(D)
: Operator
Concept of PID control
1. Proportional
gain(P):
the output is proportional to input. With only proportional gain control, there will always be
a steady-state error.
2. Integral
time(I):
the controller output is proportional to the integral of the controller input. To eliminate the
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