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
ProcessCtrlUnit]
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.
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
ProcessCtrlUnit]
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 de-
scription of
Feedback Function
, par.20-20 Feedback Function.
NOTE: 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
ProcessCtrlUnit]
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 de-
scription of par.20-20
Feedback Function.
Note
The setpoint reference entered here is added to any other references that
are enabled (see par. group 3-1*).
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 refrigerant pressure measurements into temperature
values.
Parameter Description
TR200 Programming Guide 191
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