Danfoss VLT AQUA Programming Manual

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

Contents

20-84 On Reference BandwidthRange: Function:5%* [0 - 200%] When the difference between the feedback and the setpointreference is less than the value of this parameter, the frequencyconverter’s display will show “Run on Reference”. This statuscan be communicated externally by programming the functionof a digital output forRun on Reference/No Warning [8]. In ad-dition, for serial communications, the On Reference status bit ofthe frequency converter’s Status Word will be high (1).TheOn Reference Bandwidth is calculated as a percentage ofthe setpoint reference.2.17.6. PID Controller, 20-9*This group provides the ability to manually adjust this PID Controller. By adjusting the PID Con-troller parameters the control performance may be improved. See section onPID in the chapterIntroduction to VLT AQUA Drive in the VLT AQUA Drive Design Guide for guidelines on ad-justing the PID Controller parameters.20-91 PID Anti WindupOption: Function:[0] Off[1] * OnOn [1] stops the PID Controller from integrating (adding) theerror between the feedback and the setpoint reference if it isnot possible to adjust the output frequency of the frequencyconverter to correct the error. This can occur when the fre-quency converter has reached its minimum or maximum outputfrequency or when the frequency converter is stopped.Off [0] causes the PID Controller to continue to integrate (add)the error between the feedback and setpoint reference eventhough the frequency converter cannot adjust its output fre-quency to correct this error. In this case, the integral term ofthe PID Controller may become quite large. When the PID Con-troller can again control the frequency converter’s output fre-quency, it may attempt to initially make a large change in thefrequency converter’s output frequency. This should generallybe avoided.20-93 PID Proportional GainRange: Function:0.50 * [0.00 = Off - 10.00] This parameter adjusts the output of the frequency converter’sPID Controller based on the error between the feedback and thesetpoint reference. Quick PID Controller response is obtainedwhen this value is large. However, if too large a value is used,the frequency converter’s output frequency may become un-stable.2. Parameter Description VLT ® AQUA Drive Programming Guide184 MG.20.O2.02 - VLT ® is a registered Danfoss trademark2