Danfoss VLT HVAC Drive Instruction Manual page 92

6. How to program the adjustable frequency
drive
enabled (see par. group 3-1*) will be used as
the PID controller's setpoint reference.
Multi-setpoint minimum
controller to calculate the difference between
Feedback 1 and Setpoint 1, Feedback 2 and
Setpoint 2, and Feedback 3 and Setpoint 3. It
will use the feedback/setpoint pair in which
the feedback is the farthest below its corre-
sponding setpoint reference. If all feedback
signals are above their corresponding set-
points, the PID controller will use the feed-
back/setpoint pair in which the difference
between the feedback and setpoint is the
least.
6
Multi-setpoint maximum
controller to calculate the difference between
Feedback 1 and Setpoint 1, Feedback 2 and
Setpoint 2, and Feedback 3 and Setpoint 3. It
will use the feedback/setpoint pair in which
the feedback is farthest above its correspond-
ing setpoint reference. If all feedback signals
are below their corresponding setpoints, the
PID controller will use the feedback/setpoint
pair in which the difference between the feed-
back and the setpoint reference is the least.
92
[5] sets up the PID
NOTE
If only two feedback signals are
used, the feedback that is not to
No Func-
be used must be set to
tion
in par. 20-00, 20-03 or
20-06. Note that each setpoint
reference will be the sum of its
respective parameter value
(20-11, 20-12 and 20-13) and
any other references that are
enabled (see par. group 3-1*).
[6] sets up the PID
NOTE
If only two feedback signals are
used, the feedback that is not to
be used must be set to No Func-
tion
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*).
MG.11.A4.22 - VLT
VLT ®
20-21 Setpoint 1
Value:
Ref par.3-02 - Ref
MIN
3-03 UNIT (from par. 20-12)
Function:
Setpoint 1 is used in closed-loop mode to en-
ter a setpoint reference that is used by the
adjustable frequency drive's PID controller.
Feedback Function
See the description of
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
Value:
Ref - Ref UNIT (from par.
MIN MAX
20-12)
Function:
Setpoint 2 is used in closed-loop mode to en-
ter a setpoint reference that may be used by
the adjustable frequency drive's PID control-
ler. See the description of
tion
, par. 20-20.
NOTE
The setpoint reference entered
here is added to any other ref-
erences that are enabled (see
par. group 3-1*).
20-81 PID Normal/Inverse Control
Value:
Normal
Inverse
Function:
Normal [0] causes the adjustable frequency
drive's output frequency to decrease when the
feedback is greater than the setpoint refer-
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HVAC Drive Instruction Manual
par.
MAX
0.000
, par.
0.000
Feedback Func-
[0]
[1]