Danfoss VLT FC 102 Operating Instructions Manual page 113

VLT HVAC Low Harmonic Drive Operating In-
structions
[1] Difference
[2] Average
[3] * Minimum
[4] Maximum
[5] Multi Setpoint Min
[6] Multi Setpoint Max
Difference [1] sets up the PID controller to use the difference between Feedback 1 and Feedback
2 as the feedback. Feedback 3 will not be used with this selection. Only Setpoint 1 will be used. The
sum of Setpoint 1 and any other references that are enabled (see par. group 3-1*) will be used as
the PID controller's set-point reference.
Average [2] sets up the PID Controller to use the average of Feedback 1, Feedback 2 and Feedback
3 as the feedback.
NB!
Any unused feedbacks must be set to
Source , par. 20-03 Feedback 2 Source , or par. 20-06 Feedback 3 Source . The
sum of Setpoint 1 and any other references that are enabled (see par. group
3-1*) will be used as the PID Controller's set-point reference.
Minimum [3] sets up the PID Controller to compare Feedback 1, Feedback 2 and Feedback 3 and
use the lowest value as the feedback.
NB!
Any unused feedbacks must be set to
Source , par. 20-03 Feedback 2 Source , or par. 20-06 Feedback 3 Source . Only
setpoint 1 will be used. The sum of Setpoint 1 and any other references that are
enabled (see par. group 3-1*) will be used as the PID Controller's setpoint ref-
erence.
Maximum [4] sets up the PID Controller to compare Feedback 1, Feedback 2 and Feedback 3 and
use the highest value as the feedback.
NB!
Any unused feedbacks must be set to
Source , par. 20-03 Feedback 2 Source , or par. 20-06 Feedback 3 Source .
Only Setpoint 1 will be used. The sum of Setpoint 1 and any other references that are enabled (see
par. group 3-1*) will be used as the PID Controller's setpoint reference.
Multi-setpoint minimum [5] sets up the PID 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 feed-
back/setpoint pair in which the feedback is the farthest below its corresponding setpoint reference.
If all feedback signals are above their corresponding setpoints, the PID Controller will use the feed-
back/setpoint pair in which the difference between the feedback and setpoint 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 Feedback 1 Source , par. 20-03 Feedback 2
Source or par. 20-06 Feedback 3 Source . Note that each setpoint reference will
be the sum of its respective parameter value (par. 20-21
Setpoint 2 and par. 20-23 Setpoint 3 ) and any other references that
par. 20-22
are enabled (see par. group 3-1*).
Multi-setpoint maximum [6] sets up the PID 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 feed-
back/setpoint pair in which the feedback is farthest above its corresponding setpoint reference. If
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.
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MG.16.A1.02 - VLT is a registered Danfoss trademark
6 How to Programme the Low Harmonic Drive
No Function in par. 20-00 Feedback 1
No Function in par. 20-00 Feedback 1
No Function in par. 20-00 Feedback 1
6
Setpoint 1 ,
113