all feedback signals are below their corresponding setpoints, the PID Controller will use the feed-
back/setpoint pair in which the difference between the feedback and the setpoint reference is the
least.
NB!
If only two feedback signals are used, the feedback that is not to be used must
be set to
No Function
in par. 20-00, 20-03 or 20-06. Note that each setpoint
reference will be the sum of its respective parameter value (20-21, 20-22 and
20-23) and any other references that are enabled (see par. group 3-1*).
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 setpoint 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*
[Ref
MIN
- Ref
MAX
UNIT (from par.
20-12)]
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!
If the min and max references are altered, a new PI - Autotune may be needed.
NB!
The setpoint reference entered here is added to any other references that are
enabled (see par. group 3-1*).
2.17.4 20-7* PID autotuning
The frequency converter PID Closed Loop controller (parameters 20-**, FC Closed Loop) can be auto-tuned, simplifying and saving time during com-
missioning, whilst ensuring accurate PID control adjustment. To use auto-tuning it is necessary for the frequency converter to be configured for closed
loop in par. 1-00
Configuration Mode
.
2 Parameter Description
VLT
p
Automation VT Drive FC322
Programming Guide
192
MG.20.W1.22 - VLT
p
is a registered Danfoss trademark
2
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