When Pid Control Is Used In A Constant Pressure Pump Feedback Application - Delta CP2000 Series User Manual

Chapter 12 Description of Parameter SettingsCP2000
time even if the error is small. It gradually increases the controller output to eliminate the
error until it is 0. In this way a system can be stable without steady-state error by
proportional gain control and integral time control.
3. Differential control(D):
The controller output is proportional to the differential of the controller input. During
elimination of the error, oscillation or instability may occur. The differential control can be
used to suppress these effects by acting before the error. That is, when the error is near 0,
the differential control should be 0. Proportional gain (P) + differential control (D) can be
used to improve the system state during PID adjustment.

When PID control is used in a constant pressure pump feedback application:

Set the application's constant pressure value (bar) to be the set point of PID control. The pressure
sensor will send the actual value as PID feedback value. After comparing the PID set point and
PID feedback, there will be an error. Thus, the PID controller needs to calculate the output by
using proportional gain (P), integral time (I) and differential time (D) to control the pump. It controls
the drive to have different pump speed and achieves constant pressure control by using a 4-20mA
signal corresponding to 0-10 bar as feedback to the drive.
R(L1)
S(L2)
T(L3)
 Pr.00-04 is set to 10 (Display PID analog feedback signal value (b) (%))
 Pr.01-12 Acceleration Time will be set as required
 Pr.01-13 Deceleration Time will be set as required
 Pr.00-21=0 to operate from the digital keypad
 Pr.00-20=0, the set point is controlled by the digital keypad
 Pr.08-00=1 (Negative PID feedback from analog input)
 ACI analog input Pr. 03-01 set to 5, PID feedback signal.
 Pr.08-01-08-03 will be set as required
If there is no vibration in the system, increase Pr.08-01(Proportional Gain (P))
If there is no vibration in the system, reduce Pr.08-02(Integral Time (I))
If there is no vibration in the system, increase Pr.08-03(Differential Time (D))
 Refer to Pr.08-00~08-21 for PID parameters settings.
no fuse breaker
(NFB)
R(L1)
S(L2)
T(L3)
analog si gnal common
water pump
U(T 1)
IM
V(T2)
3~
W(T 3)
F eedback 4-20mA
cor responds
0-10bar
ACI/A VI
(4- 20mA /0- 10V )
DC
- +
ACM
12.1-08-2
throttle
pressure
sensor