20-70 Closed Loop Type
Option:
Function:
This parameter defines the application
response. The default mode should be
sufficient for most applications. If the
application response speed is known, it
can be selected here. This will decrease
the time needed for carrying out PID
autotuning. The setting has no impact on
the value of the tuned parameters and is
used only for the autotuning sequence.
[0]
*
Auto
[1]
Fast Pressure
[2]
Slow Pressure
[3]
Fast Temperature
[4]
Slow Temperature
20-71 PID Performance
Option:
Function:
[0]
*
Normal Normal setting of this parameter will be suitable for
pressure control in fan systems.
[1]
Fast
Fast setting would generally be used in pumping
systems, where a faster control response is desirable.
20-72 PID Output Change
Range:
Function:
0.10
*
[0.01 -
0.50 ]
This parameter sets the magnitude of step
change during autotuning. The value is a
percentage of full speed. I.e. if maximum output
frequency in
4-13 Motor Speed High Limit [RPM]
4-14 Motor Speed High Limit [Hz]
is set to 50Hz,
0.10 is 10% of 50Hz, which is 5Hz. This parameter
should be set to a value resulting in feedback
changes of between 10% and 20% for best
tuning accuracy.
20-73 Minimum Feedback Level
Range:
Function:
-999999.000
ProcessCtrlUnit
*
[-999999.999 -
par. 20-74
ProcessCtrlUnit]
The minimum allowable
feedback level should be
entered here in User units
as defined in
20-12 Reference/Feedback
Unit
. If the level falls below
, autotuning is aborted
and an error message will
appear on the LCP.
20-74 Maximum Feedback Level
Range:
Function:
999999.000
ProcessCtrlUnit
*
[par. 20-73 -
999999.999
ProcessCtrlUnit]
The maximum allowable
feedback level should be
entered here in User units
as defined in
20-74 Maximum Feedback Level
Range:
Function:
20-12 Reference/Feedback
Unit
. If the level rises above
, autotuning is aborted
and an error message will
appear on the LCP.
20-79 PID Autotuning
Option:
Function:
This parameter starts the PID autotuning sequence.
Once the autotuning has successfully completed
and the settings have been accepted or rejected by
the user, by pressing [OK] or [Cancel] buttons on
the LCP 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 will indicate that the system has
reached the setpoint.
20-81 PID Normal/ Inverse Control
Option:
Function:
[0]
*
Normal
Normal
[0] causes the frequency converter’s output
frequency to decrease when the feedback is greater
than the setpoint reference. This is common for
pressure-controlled supply fan and pump
applications.
[1]
Inverse
Inverse
[1] causes the frequency converter’s output
frequency to increase when the feedback is greater
than the setpoint reference. This is common for
temperature-controlled cooling applications, such as
cooling towers.
20-82 PID Start Speed [RPM]
Range:
Function:
Size related
*
[0 - par. 4-13 RPM]
20-83 PID Start Speed [Hz]
Range:
Function:
Size related
*
[0.0 - par. 4-14 Hz]
Parameter Description
VLT
®
HVAC Drive Programming Guide
130
MG.11.CB.02 - VLT
®
is a registered Danfoss trademark
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