Danfoss VLT HVAC Basic Drive FC 101 Programming Manual page 89

Parameters
3.14.5 20-8* PI Basic Settings
Parameters for configuring the process PI control.
20-81 PI Normal/ Inverse Control
Option: Function:
[0] Normal Causes the frequency converter output frequency
*
to decrease when the feedback is greater than the
setpoint reference. This behavior is common for
pressure-controlled supply fan and pump
applications.
[1] Inverse Causes the frequency converter output frequency
to increase when the feedback is greater than the
setpoint reference. This behavior is common for
temperature-controlled cooling applications, such
as cooling towers.
20-83 PI Start Speed [Hz]
Range: Function:
0 Hz [ 0 - Enter the motor speed to be attained as a
*
200.0 Hz] start signal for commencement of PI control.
After power-up, the frequency converter
operates using speed open-loop control.
When the process PI start speed is reached,
the frequency converter changes to PI control.
20-84 On Reference Bandwidth
Range: Function:
5 % [0 - When the difference between the feedback and
*
200 %] the setpoint reference is less than the value of
this parameter, the frequency converter display
shows Run on Reference. This status can be
communicated externally by programming the
function of a digital output for [8] Run on
Reference/No Warning. In addition, for serial
communications, the on-reference status bit of
the frequency converter status word is high (1).
The on-reference bandwidth is calculated as a
percentage of the setpoint reference.
MG18B502
Programming Guide
3.14.6 20-9* PI Controller
20-91 PI Anti Windup
Option: Function:
[0] Off Continue regulation of an error even when the output
[1] On
*
20-93 PI Proportional Gain
Range:
0.50
*
20-94 PI Integral Time
Range:
20 s
*
9999 s]
20-97 PI Feed Forward Factor
Range:
0 %
*
400 %]
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frequency cannot be increased or decreased.
Cease regulation of an error when the output
frequency can no longer be adjusted.
Function:
[0 - 10 ] Enter the process controller proportional gain.
Quick control is obtained at high amplification.
However, if amplification is too high, the
process may become unstable.
Function:
[0.10 - Enter the process controller integral time.
Obtain quick control through a short integral
time, though if the integral time is too short,
the process becomes unstable. An excessively
long integral time disables the integral action.
Function:
[0 - Enter the PI feed forward factor. The FF factor
sends a constant fraction of the reference
signal to bypass PI control. Therefore, the PI
can affect only the remaining fraction of the
control signal. The FF factor can increase
dynamic performance.
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