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
and par. 20-23
Setpoint 3
. By selecting
Multi-setpoint minimum
, [5], in
, 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 adjustable
frequency drive’s PID controller. See the description of par. 20-20
.
NOTE!
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 ad-
justable frequency drive’s PID controller. See the description of
Feedback Function
,
.
NOTE!
The setpoint reference entered here is added to any other references that are enabled (see par. group 3-1*).
VLT
®
HVAC Drive Instruction Manual
7 How to Program the Adjustable Frequency
Drive
MG.11.AB.22 - VLT
®
is a registered Danfoss trademark
7-39
7
