Fieldbus cycle[μs]Position controlcycle[μs]Speed controlcycle[μs]Current controlcycle[μs]1000 250 250 125Table 2.3 Ethernet POWERLINK® and EtherCAT® Cycle TimesThe used cycle times can be read using object 0x201D (seechapter 7.6.1 Parameter 51-07 to 51-09: Used Task CycleTimes (0x201D)). The values are given in microseconds.There are 2 control parameter sets in the servo drive,however only 1 of them can be active at any time. Use bit15 (cs) in the Controlword to switch from 1 set to the other.Linear blending occurs from the parameter of the currentlyactive set to the new one. The blending time is defined inobject 0x201B (see chapter 7.6.2 Parameter 51-01: ControlParameter Blending Time (0x201B)).No blending takes place when writing to a value of thecurrently active control parameter set. The new value isused immediately, which could cause a jerk on the shaft.Blending is used when updating a whole set of parametersat the same time (for example, when activating CAM mode,which uses its own sets of control parameters).2.3.6.1 Position ControllerThe controller uses PD control. The D constant is the derivative time constant. The controller provides 2 sets of controlparameters that can be switched during operation (see chapter 7.7.8 Parameters 51-02, 52-04, and 52-49: Application Settings(0x2016) and chapter 7.6.4.2 Parameters 51-26 and 51-27: Position Controller Parameters 2 (0x2015)).Both sets are available as read-write objects in the object dictionary. Use a manufacturer-specific bit in the Controlword toswitch between the 2 sets of parameters.LimitfunctionLimitfunctionTorquecontrolVelocitycontrolPositioncontrolSelectorApplication torque limit (0x2053)Max torque (0x6072)Max motor speed (0x6080)Feed forward torqueFeed forward velocityPosition demandInternal value (0x60FC)Controlword (0x6040)Position controller parameters (0x2013)Speed controller parameters (0x2012)Position controller parameters 2 (0x2015)Speed controller parameters 2 (0x2014)+ + + +– – –+P D P DNotchInertiaMS130BF167.10IIllustration 2.11 Position Control LoopServo Drive Operation Programming GuideMG36D102 Danfoss A/S © 01/2017 All rights reserved. 252 2
