Danfoss VLT AutomationDrive FC 301 Design Manual

Also see for VLT AutomationDrive FC 301: Programming guide Installation guide Operating guide Installation guide Design guide

Contents

Danfoss VLT AutomationDrive FC 301 Design Manual Manual pdf 29 page image

Parameter Description of function7-33 Process PID Proportional Gain The higher the value - the quicker the control. However, too large value may lead tooscillations.7-34 Process PID Integral Time Eliminates steady state speed error. Lower value means quick reaction. However, too smallvalue may lead to oscillations.7-35 Process PID Differentiation Time Provides a gain proportional to the rate of change of the feedback. A setting of zerodisables the differentiator.7-36 Process PID Diff. Gain Limit If there are quick changes in reference or feedback in a given application - which meansthat the error changes swiftly - the differentiator may soon become too dominant. This isbecause it reacts to changes in the error. The quicker the error changes, the stronger thedifferentiator gain is. The differentiator gain can thus be limited to allow setting of thereasonable differentiation time for slow changes.7-38 Process PID Feed Forward Factor In application where there is a good (and approximately linear) correlation between theprocess reference and the motor speed necessary for obtaining that reference, the FeedForward Factor can be used to achieve better dynamic performance of the Process PIDControl.5-54 Pulse Filter Time Constant #29 (Pulseterm. 29),5-59 Pulse Filter Time Constant #33 (Pulseterm. 33),6-16 Terminal 53 Filter Time Constant (Analogterm 53),6-26 Terminal 54 Filter Time Constant (Analogterm. 54)6-36 Term. X30/11 Filter Time Constant6-46 Term. X30/12 Filter Time Constant35-46 Term. X48/2 Filter Time ConstantIf there are oscillations of the current/voltage feedback signal, these can be dampened bymeans of a low-pass filter. This time constant represents the speed limit of the ripplesoccurring on the feedback signal.Example: If the low-pass filter has been set to 0.1s, the limit speed is 10 RAD/s (thereciprocal of 0.1 s), corresponding to (10/(2 x π)) = 1.6 Hz. This means that all currents/voltages that vary by more than 1.6 oscillations per second is damped by the filter. Thecontrol is only carried out on a feedback signal that varies by a frequency (speed) of lessthan 1.6 Hz.The low-pass filter improves steady state performance, but selecting a too large filter timedeteriorates the dynamic performance of the Process PID Control.Table 3.5 Relevant Parameters for Process Control3.6.6.4 Advanced PID ControlConsult the VLT® AutomationDrive FC 301/FC 302Programming Guide for advanced PID control parameters3.6.7 Internal Current Control in VVC+ModeWhen the motor current/torque exceed the torque limitsset in 4-16 Torque Limit Motor Mode, 4-17 Torque LimitGenerator Mode and 4-18 Current Limit, the integral currentlimit control is activated.When the frequency converter is at the current limit duringmotor operation or regenerative operation, it tries to getbelow the preset torque limits as quickly as possiblewithout losing control of the motor.3.6.8 Local (Hand On) and Remote (AutoOn) ControlThe frequency converter can be operated manually via thelocal control panel (LCP) or remotely via analog and digitalinputs and serial bus. If allowed in 0-40 [Hand on] Key onLCP, 0-41 [Off] Key on LCP, 0-42 [Auto on] Key on LCP, and0-43 [Reset] Key on LCP, it is possible to start and stop thefrequency converter via the LCP pressing [Hand On] and[Off]. Alarms can be reset via [Reset]. After pressing [HandOn], the frequency converter goes into Hand mode andfollows (as default) the local reference that can be setusing the navigation keys on the LCP.After pressing [Auto On], the frequency converter entersAuto mode and follows (as default) the remote reference.In this mode, it is possible to control the frequencyconverter via the digital inputs and various serial interfaces(RS-485, USB, or an optional fieldbus). See more aboutstarting, stopping, changing ramps and parameter set-upsetc. in parameter group 5-1* Digital Inputs or parametergroup 8-5* Serial communication.130BP046.10Handon Off Autoon ResetIllustration 3.10 Operation KeysBasic Operating Principles VLT® AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kWMG33BF02 - Rev. 2013-12-20 273 3