Table Of Contents - INVT Goodrive300-01A Series Operation Manual

Goodrive300-01A series VFD for air compressor
compressor enters normal air supply state after starts. When the discharge pressure is higher than
P18.05, automatic unloading will be applied, and the VFD enters sleep state. If sleep function is
invalid, the VFD will continue running at no-load frequency P18.12. When the discharge pressure is
lower than P18.06, automatic loading will be applied, and during load-carrying running, the master
speed is controlled by pressure PID. P18.07 is used to set the air supply pressure when the air
compressor runs stably. The VFD keeps the discharge pressure constant by regulating the master
speed. Constant-pressure control adopts PID algorithm, and the frequency reference source of the
master is set by P00.06=7, the PID reference source selects P09.00 = 10, reference pressure is set
via P18.07. The feedback source of PID P09.02 = 8, which is obtained by detecting the pressure
signal. PID parameter P9.04, P9.05 and P9.06 adopts system default values.
Note: In above figure, the VFD stops as per P01.08, default setting is decelerate to stop.
Normal stop command and unloading stage are deceleration process; the VFD will change to coast to
stop during emergency-stop operation and faults.
5.3 PID commissioning
PID control, a common mode for process control, is mainly used to adjust the VFD output frequency
or output voltage through performing scale-division, integral and differential operations on the
difference between feedback signal of controlled variables and signal of the target, thus forming a
negative feedback system to keep the controlled variables above the target. It is suitable for flow
control, pressure control, temperature control, etc. Diagram of basic principles for output frequency
regulation is shown in the figure below.
Pre-set PID reference of
keypad
P09.01
Keypad
(PID reference source)
AI1
0
AI2
1
AI3
2
3
HDIA
4
Multi-step
speed
5
6
MODBUS
7
PROFIBUS\CANopen
8
Ethernet
9
HDIB
EtherCat/Profinet 10
11
PLC card
Introduction to the working principles and control methods for PID control:
Proportional control (Kp): When the feedback deviates from the reference, the output will be
proportional to the deviation, if such deviation is constant, the regulating variable will also be constant.
Proportional control can respond to feedback changes rapidly, however, it cannot eliminate the error
by itself. The larger the proportional gain, the faster the regulating speed, but too large gain will result
P09.00
PID reference
value
P17.23
+
Reference-
feedback<P09.08？
-
P09.08 (Limit of PID control
P09.02
(PID feedback source)
P17.24
PID feedback
value
Terminal function 25
PID control pause
Y
Valid
Keep current frequency
N Invalid
deviation)
Kp P09.04 (proportional gain)
AI1
Ti P09.05 (integral time)
0
AI2
Td P09.06 (differential time)
1
AI3
2
3
HDIA
4
MODBUS
5
6
PROFIBUS\CANopen
7
Ethernet
8 HDIB
EtherCat/Profinet
9
PLC card
10
-83-
Function code description
PID stops
adjustment
P09.09
（upper limit value of PID
output）
0
1
P09.03
(PID output characteristics)
P09.10
(lower limit value of PID
output)
Set frequency
P17.00
PID output