Danfoss VLT AQUA Programming Manual

Also see for vlt aqua: Instructions Design guide Instruction manual Operating instructions Design guide

Contents

if any one feedback is below the setpoint and decrease thespeed of the fan if all feedbacks are above the setpoint.Example 2 – Multi zone, multi setpointThe previous example can be used to illustrate the use of multizone, multi setpoint control. If the zones require different pres-sures for each VAV box, each setpoint may be specified in par.20-21, 20-22 and 20-23. By selectingMulti setpoint minimum,[5], in par. 20-20, Feedback Function, the PID Controller willincrease the speed of the fan if any one of the feedbacks is be-low its setpoint and decrease the speed of the fan if all feed-backs are above their individual setpoints.Sum [0] sets up the PID Controller to use the sum of Feedback1, Feedback 2 and Feedback 3 as the feedback.NB!Any unused feedbacks must be set toNo Func-tion in par. 20-00, 20-03, or 20-06.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.Difference [1] sets up the PID Controller to use the differencebetween Feedback 1 and Feedback 2 as the feedback. Feedback3 will not be used with this selection. Only setpoint 1 will beused. The sum of Setpoint 1 and any other references that areenabled (see par. group 3-1*) will be used as the PIDController’s setpoint reference.Average [2] sets up the PID Controller to use the average ofFeedback 1, Feedback 2 and Feedback 3 as the feedback.NB!Any unused feedbacks must be set toNo Func-tion in par. 20-00, 20-03, or 20-06. The sum ofSetpoint 1 and any other references that are en-abled (see par. group 3-1*) will be used as the PIDController’s setpoint reference.Minimum [3] sets up the PID Controller to compare Feedback1, Feedback 2 and Feedback 3 and use the lowest value as thefeedback.2. Parameter Description VLT ® AQUA Drive Programming Guide178 MG.20.O2.02 - VLT ® is a registered Danfoss trademark2