Danfoss VLT HVAC Series, Programming Manual, Page: 198 / 338

[1] Difference 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 setpoint reference.
[2] Average
Average
[2] sets up the PID controller to use the average of Feedback 1, Feedback 2 and Feedback
3 as the feedback.
NOTE!
Any unused feedbacks 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 . 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.
[3] * Minimum Minimum [3] sets up the PID controller to compare Feedback 1, Feedback 2 and Feedback 3 and
use the lowest value as the feedback.
NOTE!
Any unused feedbacks 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
. 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 refer-
ence.
[4] Maximum
Maximum
[4] sets up the PID controller to compare Feedback 1, Feedback 2 and Feedback 3 and
use the highest value as the feedback.
NOTE!
Any unused feedbacks 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 .
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.
[5] Multi Setpoint Min
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.
NOTE!
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 1 , par.
20-22 Setpoint 2 and par.20-23 Setpoint 3 ) and any other references that are
enabled (see par. group 3-1*).
[6] Multi Setpoint Max 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 feedback/
setpoint pair in which the difference between the feedback and the setpoint reference is the least.
3 Parameter Description VLT ® HVAC Drive Programming Guide
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