Example of Process PID Control set-up
Function
Par. no. Setting
Initialize the adjustable frequency drive
14-22
[2] Initialization - perform power cycling - press reset
1) Set motor parameters:
Set the motor parameters according to nameplate data 1-2*
As stated on motor nameplate
Perform a full
A
utomation
M
otor
A
daptation
1-29
[1] Enable complete AMA
2) Make sure that motor is running in the right direction.
When motor is connected to adjustable frequency drive with straight forward phase order as U - U; V - V; W - W motor shaft usually turns clockwise
seen into shaft end.
Press “Hand On” LCP key. Check shaft direction by ap-
plying a manual reference.
If motor turns opposite of required direction:
1. Change motor direction in par. 4-10
Motor Speed
Direction
2. Turn off line power - wait for DC link to discharge -
switch two of the motor phases
4-10
Select correct motor shaft direction.
Set configuration mode.
1-00
[3] Process
Set Local Mode Configuration
1-05
[0] Speed Open-loop
3) Set reference configuration, i.e., the range for reference handling. Set scaling of analog input in par. 6-xx
Set reference/feedback units
Set min. reference (50°F [10°C])
Set max. reference (176°F [80°C])
If set value is determined from a preset value (array
parameter), set other reference sources to No Func-
tion.
3-01
3-02
3-03
3-10
[140]°F [[60]°C] unit shown on display
23°F [-5°C]
95°F [35°C]
[0] 35%
Ref
=
Par
. 3
−
10(0)
100
× ((
Par
. 3
−
03)
−
(
par
. 3
−
02)) = 24, 5°
C
par. 3-14
Preset Relative Reference
to par. 3-18
Relative Scaling Reference Re-
source
[0] = No Function
4) Adjust limits for the adjustable frequency drive:
Set ramp times to an appropriate value as 20 sec.
3-41
3-42
20 sec.
20 sec.
Set min. speed limits
Set motor speed max. limit
Set max. output frequency
300 RPM
1500 RPM
60 Hz
Set S201 or S202 to desired analog input function (Voltage (V) or milli-Amps (I))
NOTE! Switches are sensitive - Make a power cycling keeping default setting of V
5) Scale analog inputs used for reference and feedback
Set terminal 53 low voltage
Set terminal 53 high voltage
Set terminal 54 low feedback value
Set terminal 54 high feedback value
Set feedback source
6-10
6-11
6-24
6-25
7-20
0 V
10 V
23°F [-5°C]
95°F [35°C]
[2] Analog input 54
6) Basic PID settings
Process PID Normal/Inverse
7-30
[0] Normal
Process PID Anti Wind-up
7-31
[1] On
Process PID start speed
7-32
300 rpm
Save parameters to LCP
0-50
[1] All to LCP
Optimization of the process regulator
The basic settings have now been made; all that needs to be done is to optimize the proportional gain, the integration time and the differentiation time
(par. 7-33
Process PID Proportional Gain
, par. 7-34
Process PID Integral Time
, par. 7-35
Process PID Differentiation Time
). In most processes, this can
be done by following the guidelines given below.
1.
Start the motor
2.
Set par. 7-33
Process PID Proportional Gain
to 0.3 and increase it until the feedback signal again begins to vary continuously. Then, reduce the
value until the feedback signal has stabilized. Now lower the proportional gain by 40–60%.
3.
Set par. 7-34
Process PID Integral Time
to 20 sec. and reduce the value until the feedback signal again begins to vary continuously. Increase
the integration time until the feedback signal stabilizes, followed by an increase of 15%–50%.
4.
Only use par. 7-35
Process PID Differentiation Time
for very fast-acting systems only (differentiation time). The typical value is four times the
set integral time. The differentiator should only be used when the setting of the proportional gain and the integral time has been fully optimized.
Make sure that oscillations in the feedback signal are sufficiently damped by the low-pass filter on the feedback signal.
FC 300 Design Guide
3 Introduction to AutomationDrive FC 300
MG.33.BC.22 - VLT
®
is a registered Danfoss trademark
3-21
3
