Danfoss VLT AQUA Drive FC 200 Operating Instructions Manual page 92

How to Programme the Low Ha...
The proportional band (error causing output to change
from 0-100%) can be calculated by means of the formula
( )
1
× ( Max Reference )
Proportional Gain
NOTE
Always set the desired for 20-14 Maximum Reference/Feedb.
before setting the values for the PID controller in
parameter group 20-9*.
20-94 PID Integral Time
Range: Function:
20.00 [0.01 - Over time, the integrator accumulates a
s 10000.00 contribution to the output from the PID
*
s] 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 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
20-93 PID Proportional Gain. When no
deviation is present, the output from the
proportional controller will be 0.
6.3.7 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 (4-13 Motor
Speed High Limit [RPM], 4-14 Motor Speed High
Limit [Hz]). At those two speeds, the power
consumption is automatically measured and
stored.
Before enabling Auto Set Up:
VLT AQUA Low Harmonic Drive Operating Instructions
22-20 Low Power Auto Set-up
Start of auto set-up of power data for No-Flow Power tuning.
Option:
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 Contoller as settings will be reset when
changing from Closed to Open Loop in 1-00 Configuration
Mode.
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:
[0]
[1]
22-22 Low Speed Detection
Option:
[0]
[1]
®
MG20T202 - VLT is a registered Danfoss trademark
Function:
1. Close valve(s) in order to create a no
flow condition
2. The frequency converter must be set for
Open Loop (1-00 Configuration Mode).
Note that it is important also to set
1-03 Torque Characteristics.
Function:
Disabled
*
Enabled If selecting Enabled, the Low Power Detection
commissioning must be carried out in order to
set the parameters in parameter group 22-3* for
proper operation!
Function:
Disabled
*
Enabled Select Enabled for detecting when the motor
operates with a speed as set in 4-11 Motor Speed
Low Limit [RPM] or 4-12 Motor Speed Low Limit
[Hz].
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