2.8 Control Structures2.8.1 Control PrincipleInrushR inrLoad sharing -Load sharing +LC Filter -(5A)LC Filter +(5A) BrakeResistor130BA193.14ML2 92L1 91L3 9389(+)88(-)R+82R-81U 96V 97W 98P 14-50 Rfi FilterFigure 2.23 Control StructuresThe adjustable frequency drive is a high-performance unit for demanding applications. It can handle various kinds of motorcontrol principles such as U/f special motor mode and VVCplus and can handle normal squirrel cage asynchronous motors.Short circuit behavior on this adjustable frequency drive depends on the three current transducers in the motor phases.Select between open-loop and closed-loop in 1-00 Configuration Mode.2.8.2 Control Structure Open-loop130BB153.10100%0%-100%100%P 3-13ReferencesiteLocalreferencescaled toRPM or HzAuto modeHand modeLCP Hand on,off and autoon keysLinked to hand/autoLocalRemoteReference RampP 4-10Motor speeddirectionTo motorcontrolReferencehandlingRemotereferenceP 4-13Motor speedhigh limit [RPM]P 4-14Motor speedhigh limit [Hz]P 4-11Motor speedlow limit [RPM]P 4-12Motor speedlow limit [Hz]P 3-4* Ramp 1P 3-5* Ramp 2Figure 2.24 Open-loop StructureIn the configuration shown in Figure 2.24, 1-00 Configuration Mode is set to [0] Open-loop. The resulting reference from thereference handling system or the local reference is received and fed through the ramp limitation and speed limitationbefore being sent to the motor control.The output from the motor control is then limited by the maximum frequency limit.Introduction to VLT® HVAC D... Design Guide36 Danfoss A/S © Rev. 06/2014 All rights reserved. MG11BC2222
