Danfoss vlt FC 102 Programming Guide

20-20 Feedback Function
Option: Function:
[6] Multi Setpoint
Max
Sets up the PID controller to
calculate the dierence between
feedback 1 and setpoint 1,
feedback 2 and setpoint 2, and
feedback 3 and setpoint 3. It uses
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 uses the feedback/
setpoint pair with the least
dierence between the 2.
NOTICE
If only 2 feedback signals are
used, set the non-used feedback
to [0] No Function in
•
Parameter 20-00 Feedback
1 Source.
•
Parameter 20-03 Feedback
2 Source.
•
Parameter 20-06 Feedback
3 Source.
Note that each setpoint reference
is the sum of its respective
parameter value
(parameter 20-21 Setpoint 1,
parameter 20-22 Setpoint 2, and
parameter 20-23 Setpoint 3) and
any other references that are
enabled (see parameter group 3-1*
References).
NOTICE
Set any unused feedback to [0] No function in
•
Parameter 20-00 Feedback 1 Source.
•
Parameter 20-03 Feedback 2 Source.
•
Parameter 20-06 Feedback 3 Source.
The PID controller uses the feedback resulting from the
function selected in parameter 20-20 Feedback Function 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.
•
Be transmitted over various serial communication
protocols.
The frequency converter can be congured to handle
multi-zone applications. 2 dierent multi-zone applications
are supported:
•
Multi-zone, single setpoint
•
Multi-zone, multi-setpoint
Examples 1 and 2 illustrate the dierence between the 2
applications:
Example 1 – Multi-zone, single setpoint
In an
oce building, a VAV (variable air volume) VLT
®
HVAC Drive system must ensure a minimum pressure at
selected VAV boxes. Due to the varying pressure losses in
each duct, the pressure at each VAV box cannot be
assumed to be the same. The minimum pressure required
is the same for all VAV boxes. This control method can be
set up by setting parameter 20-20 Feedback Function to [3]
Minimum, and entering the desired pressure in
parameter 20-21 Setpoint 1. If any feedback is below the
setpoint, the PID controller increases the fan speed. If all
feedbacks are above the setpoint, the PID controller
decreases the fan speed.
Parameter Descriptions Programming Guide
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Danfoss vlt FC 102 Specifications

General

Category	DC Drives
Model	Danfoss VLT FC 102
Output voltage range	0 to rated motor voltage
Power range	0.37 kW to 200 kW
Communication interfaces	RS-485
Protection features	Overvoltage, undervoltage, overcurrent, short circuit, earth fault, overtemperature, motor thermal protection
Cooling method	Air-cooled
Enclosure rating	IP20, IP21, IP55 (depending on model)
Approvals	CE, UL, cUL