Danfoss VLT Programming Guide

Example 2 – Multi zone, multi setpoint
The previous example can be used to illustrate the use of multi zone, multi setpoint control. If the zones require different pressures for each VAV box,
each setpoint may be specified in par. 20-21
Setpoint 1 , par. 20-22 Setpoint 2 and par. 20-23 Setpoint 3 . By selecting Multi setpoint minimum , [5], in
par. 20-20
Feedback Function , the PID Controller will increase the speed of the fan if any one of the feedbacks is below its setpoint and decrease the
speed of the fan if all feedbacks are above their individual setpoints.
20-21 Setpoint 1
Range: Function:
0.000 Proc-
essCtrlU-
nit*
[-999999.999 - 999999.999 Proc-
essCtrlUnit]
Setpoint 1 is used in Closed Loop Mode to enter a setpoint reference that is used by the frequency
converter’s PID Controller. See the description of par. 20-20
Feedback Function .
NB!
Setpoint reference entered here is added to any other references that are enabled
(see par. group 3-1*).
20-22 Setpoint 2
Range: Function:
0.000 Proc-
essCtrlU-
nit*
[-999999.999 - 999999.999 Proc-
essCtrlUnit]
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 , par. 20-20 Feedback
Function
.
NB!
The set-point reference entered here is added to any other references that are enabled (see par. group 3-1*).
20-23 Setpoint 3
Range: Function:
0.000 Proc-
essCtrlU-
nit*
[-999999.999 - 999999.999 Proc-
essCtrlUnit]
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 par. 20-20
Feedback Function .
NB!
The setpoint reference entered here is added to any other references that are
enabled (see par. group 3-1*).
3 Parameter Description VLT
®
HVAC Drive Programming Guide
182 MG.11.C9.02 - VLT
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is a registered Danfoss trademark
3

Danfoss VLT Specifications

General

Frequency	50/60 Hz
Enclosure	IP20, IP21, IP55, IP66
Series	VLT
Control Technique	Flux Vector Control
Output Voltage	0-Vinput
Control Method	Fieldbus
Communication Interface	PROFIBUS, CANopen
Protection Features	Overload, Overvoltage, Undervoltage, Short Circuit, Ground Fault
Cooling Method	Liquid Cooled
Storage Temperature	-25°C to +70°C
Relative Humidity	5-95% non-condensing
Altitude	Up to 1000m (3280ft) without derating, up to 4000m (13120ft) with derating
Operating Temperature	-10°C to +50°C (14°F to 122°F)