Danfoss MCO 305 Design Manual

Also see for MCO 305: Operating instructions Operating instructions Design guide

MCO 305 Design Guide__ Parameter Reference __¾ default setting [ ] value for use in communication via serial communication port224 MG.33.L5.02 – VLT® is a registered Danfoss trademark33-25 Marker Number for ReadySYNCREADYRange0 – 10000 ¾ 1FunctionSYNCREADY defines how often during a markersynchronization (SYNCM and SYNCCMM) a synchro-nization evaluation with ACCURACY must becompleted with accuracy so that ready is fulfilled.ACCURACY is checked during every correction. IfACCURACY is fulfilled then 1 is added until the setmarker number has been achieved.Synchronization evaluation is always executed afterm marker pulses by the master par. 33-15 MarkerNumber for Master.ACCURAY and READY can be queried using SYNCSTAT.33-26 Velocity FilterSYNCVFTIMERange [Unit]–MLONG – MLONG [μs]–999 – 999 = standard table¾ 0Standard Tableencoder resolution τ_filt [μs]250 39500256 38600500 19500512 190001000 95001024 93002000 45002048 44002500 35004096 19005000 1400FunctionThis parameter configures the velocity filter which isused for the velocity synchronization. Since the ve-locity synchronization only uses the currently activemaster velocity and the values can decrease to verysmall values (e.g. 2 qc/ms), a small fluctuation invelocity can have dramatic effects. In order to eventhis out the following filter function is applied:Cmdvel =Old_Cmdvel + (Actvel – Old_Cmdvel) * ms/τ_filtWith the following:Cmdvel = set velocityOld_Cmdvel = last set velocityActvel = actual velocity of the masterms = sampling time (fixed 1ms)τ_filt = filter time constantsGenerally the value for τ_filt is taken from a table,depending on the Encoder counts per revolution ofthe master. This value can be overwritten by theparameter Velocity Filter and is always used whenVelocity Filter is not equal zero.If the speed filter is defined with a negativenumber, the corresponding value also applies forangle/position synchronization SYNCP and formarker correction SYNCM.In this case filtering takes place as describedabove, but the errors made are summed up. Thiserror sum is taken into the calculation with1000/(τ*10) in each case, so that no positiondeviation can occur over prolonged periods.The value returned by SYNCERR always containsthe error made so that this is also used for the eva-luation of the synchronicity. In the case of markercorrection the correction value is balanced moreslowly and with the same factor as the error sums.If, for example, a filter factor of –100000 (100 ms)is used, a marker correction is balanced within1 second (100 ms * 10). This allows a ‘taming’ of thesynchronization without restricting the acceleration.33-27 Offset Filter TimeSYNCOFFTIMERange [Unit]0 – MLONG [ms] ¾ 0FunctionCompensation velocity of an offset (1. synchronize;2. new offset)The Offset Filter Time also influences the way, howa new Position Offset for Synchronization (par. 33-12) value is handled. The offset which has to berealized will be done step by step. The step whichis realized every sample time (ms) is calculated asfollows:part)(integereFilter TimOffset27-33par.DistanceMarkerMaster17-33par.sizestep =So it will take Offset Filter Time to realize an offsetof par. 33-17 Master Marker Distance. The OffsetFilter Time also has influence on the marker startcorrection and on the correction of marker error(see par. 33-29 Filter Time for Marker Correction).