Danfoss VLT AQUA Instruction Manual page 143

VLT AQUA High Power Instruction Manual
20-82 PID Start Speed [RPM]
Range:
Application [Application dependant]
dependent*
20-93 PID Proportional Gain
Range:
0.50 N/A* [0.00 - 10.00 N/A]
If (error x gain) jumps with a value equal to that set in par. 20-14
Motor Speed High Limit [RPM]
equal to that set in par. 4-13
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 par. 20-14
20-94 PID Integral Time
Range:
20.00 s* [0.01 - 10000.00 s]
Function:
Function:
The proportional gain indicates the number of times the error between the set point and the feed-
back signal is to be applied.
Maximum Reference/Feedb.
Motor Speed High Limit [Hz]
/par. 4-14
)
Maximum Reference/Feedb. before setting the values for the PID controller in par. group 20-9*.
Function:
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
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
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 par. 20-93,
from the proportional controller will be 0.
®
MG.20.P3.22 - VLT is a registered Danfoss trademark
5 How to program the adjustable frequency
, the PID controller will try to change the output speed
but in practice of course limited by this setting.
Proportional Gain
. When no deviation is present, the output
drive
5
5-37