Danfoss VLT FC 360 Design Manual

Also see for VLT AutomationDrive FC 360: Quick guide Quick guide Quick guide Programming guide Programming guide

Contents

Danfoss VLT FC 360 Design Manual Manual pdf 26 page image

2.5 PID Control2.5.1 Speed PID Control1-00 Configuration Mode 1-01 Motor Control PrincipleU/f VVCplus[0] Speed open loop Not Active Not Active[1] Speed closed loop N.A. ACTIVE[2] Torque N.A. Not Active[3] Process Not Active Not ActiveTable 2.3 Control Configurations, Active Speed Control“N.A.” means that the specific mode is not available at all. “Not Active” means that the specific mode is available but the Speed Control is notactive in that mode.The following parameters are relevant for the Speed Control:Parameter Description of function7-00 Speed PID Feedback Source Select from which input the Speed PID should get its feedback.7-02 Speed PID Proportional Gain The higher the value - the quicker the control. However, too high value may lead to oscillations.7-03 Speed PID Integral Time Eliminates steady state speed error. Lower value means quicker reaction. However, too low value maylead to oscillations.7-04 Speed PID DifferentiationTimeProvides a gain proportional to the rate of change of the feedback. A setting of zero disables thedifferentiator.7-05 Speed PID Diff. Gain Limit If there are quick changes in reference or feedback in a given application - which means that the errorchanges swiftly - the differentiator may soon become too dominant. This is because it reacts tochanges in the error. The quicker the error changes, the stronger the differentiator gain is. The differ-entiator gain can thus be limited to allow setting of the reasonable differentiation time for slowchanges and a suitably quick gain for quick changes.7-06 Speed PID Lowpass FilterTimeA low-pass filter that dampens oscillations on the feedback signal and improves steady stateperformance. However, too large filter time will deteriorate the dynamic performance of the Speed PIDcontrol.Practical settings of parameter 7-06 taken from the number of pulses per revolution on from encoder(PPR):Encoder PPR 7-06 Speed PID Lowpass FilterTime512 10 ms1024 5 ms2048 2 ms4096 1 msTable 2.4 Speed Control ParametersProduct Overview VLT® AutomationDrive FC 360 Design Guide24 MG06B202 - VLT® is a registered Danfoss trademark22