20-83 PID Start Speed [Hz]
Range:
Function:
Application
dependent*
[Application dependant]
20-84 On Reference Bandwidth
Range:
Function:
5 %*
[0 - 200 %]
When the difference between the feedback and 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
Run on Reference/No
Warning
[8]. 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.
2.17.6 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 on
PID
in the chapter
Introduction to VLT Automation VT Drive
in the
VLT Automation VT Drive Design Guide
for guidelines
on adjusting the PID Controller parameters.
20-91 PID Anti Windup
Option:
Function:
[0]
Off
Off
[0] The integrator will continue to change value also after output has reached one of the ex-
tremes. This can afterwards cause a delay of change of the output of the controller.
[1] *
On
On
[1] 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.
20-93 PID Proportional Gain
Range:
Function:
2.00*
[0.00 - 10.00 ]
If (Error x Gain) jumps with a value equal to what is set in par. 20-14
Maximum Reference/Feedb.
the PID controller will try to change the output speed
equal to what is set in par. 4-13
Motor Speed High Limit [RPM]
/par. 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:
(
1
Proportional
Gain
)
× (
Max
Reference
)
NB!
Always set the desired for par. 20-14
Maximum Reference/Feedb.
before setting the values for the PID controller in par. group 20-9*.
VLT
p
Automation VT Drive FC322
Programming Guide
2 Parameter Description
MG.20.W1.22 - VLT
p
is a registered Danfoss trademark
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