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 portMG.33.L5.02 – VLT® is a registered Danfoss trademark 21132-63 Limit Value for Integral SumKILIMRange0 – 1000 ¾ 10000 = Integral offFunctionThis parameter limits the integral sum in order toavoid instability and PID wind-up in case of feed-back error.32-64 PID BandwidthBANDWIDTH - 35Range [unit]0 – 1000 [1/10 %]0 = PID off¾ 1000FunctionThe value 1000 means that the PID filter can out-put the full command value. For a Bandwidth of500 only 50 % of the set value is output. Thus,values less than 1000 limit the P-share accordingly.The bandwidth in which the PID controller shouldfunction can be limited, for example to avoid thebuilt-up of a vibration in case of a system whichcould be jeopardized by vibrations.However, then it is necessary to enter considerablyhigher values for the parameters 32-65 Velocityand 32-66 Acceleration Feed-forward in order toachieve the corresponding control. A systemadjusted in such a manner is not as dynamic as itcould be, but is considerably more stable and tendsto experience less uncontrolled vibrations.32-65 Velocity Feed-forwardFFVELRange0 – 100000 ¾ 0FunctionWhen a control has a limited Bandwidth then abase velocity must be set so that it can be ruledout that the control will entirely prevent the drivefrom running due to the limit set.Velocity Feed-forward indicates the value withwhich the velocity forward feed is completed.When working with a normal PID algorithm theFFVEL must always be the same as the D factor inorder to achieve typical dampening D.32-66 Acceleration Feed-forwardFFACCRange0 – 100000 ¾ 0FunctionSet the base acceleration whenever you havelimited the bandwidth. Thus you will prevent thecontrol from not accelerating at all due to the limitset. Acceleration Feed-forward indicates the valuewith which the acceleration forward feed iscompleted.For a normal PID algorithm this value is equal to 0.32-67 Max. Tolerated Position ErrorPOSERRRange [unit]1 – MLONG [qc] ¾ 20000FunctionThe Maximum Tolerated Position Error defines thetolerance allowed between the current actualposition and the calculated command position. Ifthe value defined with POSERR is exceeded thenthe position control is turned off and a positionerror is triggered.The Position Error does not affect the positioningaccuracy, but merely determines how precisely thetheoretically calculated path of motion must befollowed, without an error being triggered.NB!:For safety reasons the Position Errorselected should not be too large since thiscould be dangerous for both the machineand its operator.NB!:On the other hand, if the values for theMaximum Tolerated Position Error are toosmall this could result in frequent errors.As a guideline, it is wise to set the quadruple ofencoder counts per revolution. This corresponds toone encoder rotation.