Danfoss VLT HVAC Drive FC 102 Programming Manual page 151

Parameter Descriptions
20-79 PID Autotuning
Option: Function:
or rejected by the user, by pressing [OK] or
[Cancel] at the end of tuning, this parameter is
reset to [0] Disabled.
[0] Disabled
*
[1] Enabled
3.18.6 20-8* PID Basic Settings
This parameter group is used to configure the basic
operation of the frequency converter's PID controller,
including how it responds to a feedback that is above or
below the setpoint, the speed at which it first starts
functioning, and when it indicates that the system has
reached the setpoint.
20-81 PID Normal/ Inverse Control
Option: Function:
[0] Normal The frequency converter's output frequency
*
decreases when the feedback is greater than the
setpoint reference. This behaviour is common for
pressure-controlled supply fan and pump
applications.
[1] Inverse The frequency converter's output frequency
increases when the feedback is greater than the
setpoint reference. This behaviour is common for
temperature-controlled cooling applications, such
as cooling towers.
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 is reached, the
frequency converter automatically switches
to closed-loop mode and the PID
controller begins to function. This is useful
in applications that require quick
acceleration to a minimum speed at start-
up.
NOTICE
This parameter is only visible if
parameter 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. 4-14 started, it initially ramps up to this output
*
Hz] frequency in open-loop mode, following
MG11CE02
Programming Guide
20-83 PID Start Speed [Hz]
Range:
20-84 On Reference Bandwidth
Range:
5 %
*
200 %]
3.18.7 20-9* PID Controller
This group provides the ability to manually adjust the PID
controller. By adjusting the PID controller parameters, the
control performance may be improved. See the VLT
Drive FC 102 Design Guide, for guidelines on adjusting the
PID controller parameters.
20-91 PID Anti Windup
Option: Function:
[0] Off The integrator continues to change value also after
[1] On
*
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Function:
the active ramp-up time. When the output
frequency programmed is reached, the
frequency converter automatically switches
to closed-loop mode and the PID controller
begins to function. This is useful in
applications that require quick acceleration
to a minimum speed at start-up.
NOTICE
This parameter is only visible if
parameter 0-02 Motor Speed Unit is
set to [1] Hz.
Function:
[0 - When the difference between the feedback and
the setpoint reference is less than the value of
this parameter, the frequency converter's 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's status word is high (1).
The On Reference Bandwidth is calculated as a
percentage of the setpoint reference.
output has reached 1 of the extremes. This can
afterwards cause a delay of change of the output of
the controller.
The integrator is locked if the output of the built-in
PID controller has reached 1 of the extremes
(minimum or maximum value) and therefore is not
able to add further changes to the value of the
process parameter controlled. This allows the controller
to respond more quickly when it can control the
system again.
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HVAC
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