Danfoss VLT AutomationDrive FC 360 Design Manual

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Danfoss VLT AutomationDrive FC 360 Design Manual Manual pdf 20 page image

Avoid EMC noise on serial communicationThis terminal is connected to ground via an internal RClink. Use twisted-pair cables to reduce interferencebetween conductors. The recommended method is shownin Illustration 2.10.PEFCPEFC130BB923.12PE PE69686169686112<10 mm1 Minimum 16 mm2 (6 AWG)2 Equalising cableIllustration 2.10 Twisted-pair CablesAlternatively, the connection to terminal 61 can beomitted.PEFCPEFC130BB924.12PE PE6969686812<10 mm1 Minimum 16 mm2 (6 AWG)2 Equalising cableIllustration 2.11 Twisted-pair Cables without Terminal 612.3 Control Structures2.3.1 Control PrincipleA frequency converter rectifies AC voltage from mains intoDC voltage, after which this DC voltage is converted intoan AC current with a variable amplitude and frequency.The motor is supplied with variable voltage/current andfrequency, enabling infinitely variable speed control of 3-phased, standard AC motors and permanent magnetsynchronous motors.2.3.2 Control ModesThe frequency converter is capable of controlling eitherthe speed or the torque on the motor shaft. Setting1-00 Configuration Mode determines the type of control.Speed controlThere are 2 types of speed control:• Speed open loop control, which does not requireany feedback from the motor (sensorless).• Speed closed loop PID control, which requires aspeed feedback to an input. A properly optimisedspeed closed loop control has higher accuracythan a speed open loop control.Select which input to use as speed PID feedback in7-00 Speed PID Feedback Source.Torque controlThe torque control function is used in applications wherethe torque on motor output shaft is controlling theapplication as tension control. Torque control can beselected in 1-00 Configuration Mode. Torque setting is doneby setting an analog, digital, or bus controlled reference.When running torque control, it is recommended to run afull AMA procedure, because correct motor data isimportant in achieving optimal performance.• Closed loop in VVC+ mode. This function is usedin applications with low to medium dynamicvariation of shaft, and offers excellentperformance in all 4 quadrants and at all motorspeeds. The speed feedback signal is mandatory.It is recommended to use MCB102 option card.Ensure the encoder resolution is at least 1024PPR, and the shield cable of the encoder is wellgrounded, because the accuracy of the speedfeedback signal is important. Tune 7-06 Speed PIDLowpass Filter Time to get the best speedfeedback signal.• Open loop in VVC+ mode. The function is used inmechanically robust applications, but theaccuracy is limited. Open loop torque functionworks for 2 directions. The torque is calculated onthe basis of the internal current measurement inthe frequency converter.Speed/torque referenceThe reference to these controls can be either a singlereference or the sum of various references includingrelatively scaled references. Reference handling isexplained in detail in chapter 2.4 Reference Handling.Product Overview Design Guide18 Danfoss A/S © 09/2014 All rights reserved. MG06B40222