Danfoss VLT 5000 Operating Instructions Manual

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Danfoss VLT 5000 Operating Instructions Manual Manual pdf 46 page image

Synchronizing controllerMG.10.N4.02 - VLT is a registered Danfoss trademark 45How to optimize the controller:Synchronization is obtained via two main elements of the controller: Velocity feed forward andthe PID controller.NOTE: Before starting the optimizing procedures it is important to select the right type ofsynchronization in parameter 728, in this example it must be “0” for velocity synchronization.Please always have the necessary degree of accuracy in mind, you could go on optimizing for along time, but it might not be necessary to have a 100% accuracy in the application you aredealing with.First step is to optimize velocity feed forward this can be done via the automatic calculationfunction:Velocity feed forward calculation is activated by setting parameter 729 to “1”, remember tomake the required parameter settings according to the description of par. 729 before startingthe calculation. The calculation is done when the value of par. 729 returns to “0”.Velocity feed forward can also be optimized manually by the following procedure:1. Set parameter 706 PID bandwidth to “0”.2. Set parameter 719 maximum track error to a high value (e.g. 1,000,000).3. Set parameter 707 velocity feed forward to 100.4. Start test-run with virtual master with a known velocity via input 3 = 1.5. Increase parameter 707 while watching master and slave velocity (press[DISPLAY/STATUS] to get the velocity readouts). You have found the optimal velocityfeed forward when slave velocity is approximately equal to the master velocity.6. Stop test-run by input 3 = 0.7. Reset parameter 719 to the original value.8. Reset parameter 706 to 1000.Second step is to optimize the PID controller, a good starting point can be found be means ofthe automatic calculation function:By setting parameter 729 to “2” velocity feed forward calculation is activated as well ascalculation of PID sample time and P/D factors, remember to make the required parametersettings according to the description of par. 729 before starting the calculation. Thecalculation is done when the value of par. 729 returns to “0”.Using the test run functions can optimize the PID factors further:There is two types of test run available: Positioning where the slave drive moves a specificdistance and Synchronizing with virtual master where the slave follows the virtual master inposition or speed. Generally it is better to use test run with virtual master as that comescloser to the operating conditions in synchronizing mode (program 2).For test run with positioning the following parameters must be set:Parameter 725 Test run speed: Record the speed as a percentage of the maximum speedof parameter 716.Parameter 726 Test run acceleration: record the acceleration time in per cent. 100% isminimum acceleration. 50% is half as fast as minimum acceleration, theramp time will thus be twice as long.Parameter 727 Test run distance: Record the distance (quad counts) for the drive to runduring optimization.