Danfoss VLT FC 103 Programming Manual page 120

Parameter Description
20-82 PID Start Speed [RPM]
Range: Function:
Size [ 0 - When the frequency converter is first
related par. 4-13 started, it initially ramps up to this output
*
RPM] speed in Open Loop Mode, following the
active Ramp Up Time. When the output
speed programmed here is reached, the
frequency converter will automatically
switch to Closed Loop Mode and the PID
Controller will begin to function. This is
useful in applications in which the driven
load must first quickly accelerate to a
minimum speed when it is started.
NOTE
This parameter will only be visible if
0-02 Motor Speed Unit is set to [0] RPM.
20-83 PID Start Speed [Hz]
Range: Function:
Size [ 0 - When the frequency converter is first
related par. started, it initially ramps up to this output
*
4-14 frequency in Open Loop Mode, following
Hz] the active Ramp Up Time. When the output
frequency programmed here is reached, the
frequency converter will automatically
switch to Closed Loop Mode and the PID
Controller will begin to function. This is
useful in applications in which the driven
load must first quickly accelerate to a
minimum speed when it is started.
NOTE
This parameter will only be visible if
0-02 Motor Speed Unit is set to [1] Hz.
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's display
will show "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's Status Word will be
high (1).
The On Reference Bandwidth is calculated as a
percentage of the setpoint reference.
®
VLT Refrigeration Drive Programming Guide
3.15.7 20-9* PID Controller
This group provides the ability to manually adjust this PID
Controller. By adjusting the PID Controller parameters the
control performance may be improved. See section PID in
the VLT Refrigeration Drive FC 103 Design Guide for
guidelines on adjusting the PID Controller parameters.
20-91 PID Anti Windup
Option:
[0]
[1]
20-93 PID Proportional Gain
Range:
0.50
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
(
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*.
®
MG16H102 - VLT is a registered Danfoss trademark
Function:
Off [0] Off The integrator will continue to change value
also after output has reached one of the extremes.
This can afterwards cause a delay of change of the
output of the controller.
On [1] On The integrator will be locked if the output of
*
the built in PID controller has reached one of the
extremes (min or max value) and therefore not able to
add further change to the value of the process
parameter controlled. This allows the controller to
respond more quickly when it again can control the
system.
Function:
[0 - 10 ] The proportional gain indicates the number of
*
times the error between the set point and the
feedback signal is to be applied.
)
1
× ( Max Reference )
3 3
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