Danfoss vlt aqua Programming Guide

[180] HP This parameter determines the unit that is used for the setpoint
reference and feedback that the PID Controller will use for con-
trolling the output frequency of the frequency converter.
2.17.3. 20-2* Feedback & Setpoint
This parameter group is used to determine how the frequency converter’s PID Controller will use
the three possible feedback signals to control the output frequency of the frequency converter.
This group is also used to store the three internal setpoint references.
20-20 Feedback Function
Option: Function:
[0] Sum
[1] Difference
[2] Average
[3]
*
Minimum
[4] Maximum
[5] Multi setpoint min
[6] Multi setpoint max This parameter determines how the three possible feedbacks
will be used to control the output frequency of the frequency
converter.
NB!
Any unused feedback must be set to “No function”
in its Feedback Source parameter: 20-00, 20-03
or 20-06.
The feedback resulting from the function selected in par. 20-20
will be used by the PID Controller to control the output fre-
quency 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.
The frequency converter can be configured to handle multi zone
applications. Two different multi zone applications are suppor-
ted:
• Multi zone, single setpoint
• Multi zone, multi setpoint
The difference between the two is illustrated by the following
examples:
Example 1 – Multi zone, single setpoint
In an office building, a VAV (variable air volume) water 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
Feedback Function , par. 20-20
to option [3], Minimum, and entering the desired pressure in
par. 20-21. The PID Controller will increase the speed of the fan
VLT
®
AQUA Drive Programming Guide 2. Parameter Description
MG.20.O2.02 - VLT
®
is a registered Danfoss trademark 177
2

Danfoss vlt aqua Specifications

General

Supply Voltage	200-240V, 380-500V, 525-600V
Enclosure	IP20
Features	Energy optimization
Approvals	CE, UL, cUL
Input Voltage Range	200-240V, 380-500V, 525-600V
Output Voltage Range	0 to supply voltage
Protection Features	Overvoltage, Undervoltage, Overcurrent, Short circuit, Ground fault
Communication Interfaces	PROFIBUS
Cooling Method	Air-cooled