If (Error x Gain) jumps with a value equal to what is set in
20-14 Maximum Reference/Feedb.
the PID controller will try
to change the output speed equal to what is set in
4-13 Motor Speed High Limit [RPM]
/
4-14 Motor Speed High
Limit [Hz]
but in practice of course limited by this setting.
The proportional band (error causing output to change
from 0–100%) can be calculated by means of the formula:
(
1
Proportional Gain
)
× (
Max Reference)
20-94 PID Integral Time
Range:
Function:
20.00
s
*
[0.01 -
10000.00
s]
Over time, the integrator accumulates a
contribution to the output from the PID
controller as long as there is a deviation
between the reference/setpoint and
feedback signals. The contribution is propor-
tional to the size of the deviation. This
ensures that the deviation (error)
approaches zero.
Quick response on any deviation is obtained
when the integral time is set to a low value.
Setting it too low, however, may cause the
control to become unstable.
The value set is the time needed for the
integrator to add the same contribution as
the proportional part for a certain deviation.
If the value is set to 10,000, the controller
will act as a pure proportional controller
with a P-band based on the value set in
. When no
deviation is present, the output from the
proportional controller will be 0.
6.2.8 22-** Miscellaneous
This group contains parameters used for monitoring water/
wastewater applications.
22-20 Low Power Auto Set-up
Start of auto set-up of power data for No-Flow Power tuning.
Option:
Function:
[0]
*
OFF
[1]
Enabled When set for
Enabled
, an auto set-up sequence is
activated, automatically setting speed to approx.
50% and 85% of rated motor speed (
4-14 Motor Speed High
Limit [Hz]
). At those two speeds, the power
consumption is automatically measured and
stored.
Before enabling Auto Set-up:
22-20 Low Power Auto Set-up
Start of auto set-up of power data for No-Flow Power tuning.
Option:
Function:
1.
Close valve(s) in order to create a no-
flow condition
2.
The adjustable frequency drive must be
set for open-loop (
Note that it is important also to set
1-03 Torque Characteristics
.
NOTE!
Auto set-up must be done when the system has reached
normal operating temperature!
NOTE!
It is important that the
4-13 Motor Speed High Limit [RPM]
or
4-14 Motor Speed High Limit [Hz]
is set to the max.
operational speed of the motor!
It is important to do the auto set-up before configuring
the integrated PI controller as settings will be reset when
changing from closed to open-loop in
.
NOTE!
Carry out the tuning with the same settings in
1-03 Torque
Characteristics
, as for operation after the tuning.
22-21 Low Power Detection
Option:
Function:
[0]
*
Disabled
[1]
Enabled If selecting Enabled, the low power detection
commissioning must be carried out in order to
set the parameters in group AP-3# for proper
operation!
22-22 Low Speed Detection
Option:
Function:
[0]
*
Disabled
[1]
Enabled Select Enabled for detecting when the motor
operates with a speed as set in
or
4-12 Motor Speed Low Limit
[Hz]
.
How to program the adjustab...
VLT AQUA 12-Pulse High Power Instruction Manual
MG.20.Y1.22 - VLT
®
is a registered Danfoss trademark
6-25
6
6
