Danfoss VLT AQUA FC 202 Operating Instructions Manual page 105

How to programme the freque...
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
Max Reference
×
Proportional Gain
NOTICE
Always set the desired for 20-14 Maximum Reference/
Feedb. before setting the values for the PID controller in
parameter group 20-9* PID Controller.
20-94 PID Integral Time
Range: Function:
8 s [0.01 - Over time, the integrator accumulates a contri-
*
10000 s] bution to the output from the PID controller as
long as there is a deviation between the
Reference/Setpoint and feedback signals. The
contribution is proportional 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 acts as
a pure proportional controller with a P-band
based on the value set in parameter 20-93 PID
Proportional Gain. When no deviation is present,
the output from the proportional controller is 0.
5.2.9 22-0* 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
(parameter 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 Drive FC 202 Operation Instructions
22-20 Low Power Auto Set-up
Start of auto set-up of power data for No-Flow Power tuning.
Option:
NOTICE
Auto Set-up must be done when the system has reached
normal operating temperature!
NOTICE
It is important that the parameter 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
parameter 1-00 Configuration Mode.
NOTICE
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] Disabled
[1] Enabled The Low Power Detection commissioning must be
22-22 Low Speed Detection
Option:
[0] Disabled
[1] Enabled Detects when the motor operates with a speed as
MG20P402 - Rev. 2013-12-16
Function:
1. Close valve(s) to create a no flow
condition
2. The frequency converter must be set for
Open Loop (parameter 1-00 Configuration
Mode).
Note that it is important also to set
1-03 Torque Characteristics.
Function:
carried out to set the parameters in parameter
group 22-3* No-Flow Power Tuning for proper
operation.
Function:
set in parameter 4-11 Motor Speed Low Limit [RPM]
or 4-12 Motor Speed Low Limit [Hz].
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