Danfoss VLT FC 103 Programming Manual page 116

Parameter Description
20-20 Feedback Function
Option: Function:
NOTE
If only two feedback signals are used, the
feedback that is not to be used must be
set to No Function in 20-00 Feedback 1
Source, 20-03 Feedback 2 Source or
20-06 Feedback 3 Source. Note that each
setpoint reference will be the sum of its
respective parameter value (20-21 Setpoint
1, 20-22 Setpoint 2 and 20-23 Setpoint 3)
and any other references that are enabled
(see parameter group 3-1*).
[6] Multi [6] Multi-setpoint maximum sets up the PID
Setpoint Controller to calculate the difference between
Max Feedback 1 and Setpoint 1, Feedback 2 and
Setpoint 2, and Feedback 3 and Setpoint 3. It
will use the feedback/setpoint pair in which the
feedback is farthest above its corresponding
setpoint reference. If all feedback signals are
below their corresponding setpoints, the PID
Controller will use the feedback/setpoint pair in
which the difference between the feedback and
the setpoint reference is the least.
NOTE
If only two feedback signals are used, the
feedback that is not to be used must be
set to No Function in 20-00 Feedback 1
Source, 20-03 Feedback 2 Source or
20-06 Feedback 3 Source. Note that each
setpoint reference will be the sum of its
respective parameter value (20-21 Setpoint
1, 20-22 Setpoint 2 and 20-23 Setpoint 3)
and any other references that are enabled
(see parameter group 3-1*).
NOTE
Any unused feedback must be set to "No function" in its
Feedback Source parameter: 20-00 Feedback 1 Source,
20-03 Feedback 2 Source or 20-06 Feedback 3 Source.
The feedback resulting from the function selected in
20-20 Feedback Function will be used by the PID Controller
to control the output frequency of the frequency
converter. This feedback can also be shown on the
frequency converter's display, be used to control a
frequency converter's analog output, and be transmitted
over various serial communication protocols.
20-21 Setpoint 1
Range:
0 [-999999.999 -
ProcessCtrlUnit 999999.999
*
ProcessCtrlUnit]
®
VLT Refrigeration Drive Programming Guide
Function:
Setpoint 1 is used in Closed
Loop Mode to enter a
setpoint reference that is
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20-21 Setpoint 1
Range:
20-22 Setpoint 2
Range:
0 [-999999.999 -
ProcessCtrlUnit 999999.999
*
ProcessCtrlUnit]
NOTE
The set-point reference entered here is added to any other
references that are enabled (see parameter group 3-1*).
20-23 Setpoint 3
Range:
0 [-999999.999 -
ProcessCtrlUnit 999999.999
*
ProcessCtrlUnit]
3.15.3 20-3* Feedback Adv. Conversion
In air conditioning compressor applications it is often
useful to control the system based on the temperature of
the refrigerant. However, it is generally more convenient to
directly measure its pressure. This parameter group allows
the frequency converter's PID Controller to convert
Function:
used by the frequency
converter's PID Controller.
See the description of
20-20 Feedback Function.
NOTE
Setpoint reference
entered here is added to
any other references
that are enabled (see
parameter group 3-1*).
Function:
Setpoint 2 is used in
Closed Loop Mode to
enter a setpoint reference
that may be used by the
frequency converter's PID
Controller. See the
description of Feedback
Function, 20-20 Feedback
Function.
Function:
Setpoint 3 is used in Closed
Loop Mode to enter a
setpoint reference that may
be used by the frequency
converter's PID Controller.
See the description of
20-20 Feedback Function.
NOTE
The setpoint reference
entered here is added to
any other references
that are enabled (see
parameter group 3-1*).
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