SINAMICS S120 Functi.. - Gregbotos.com

Operating ModesVector controlIf the speed controller has been correctly adjusted, it only has to compensate fordisturbance variables in its own control loop, which can be achieved by means of arelatively small change to the correcting variables. Speed setpoint changes, on theother hand, are carried out without involving the speed controller and are, therefore,performed more quickly.The effect of the pre-control variable can be adapted according to the applicationvia the evaluation factor p1496. If p1496 = 100 %, pre-control is calculated in accordancewith the motor and load moment of inertia (p0341, p0342). A balancingfilter is used automatically to prevent the speed controller from acting against theinjected torque setpoint. The time constant of the balancing filter corresponds tothe equivalent delay time of the speed control loop. Speed controller pre-control iscorrectly set (p1496 = 100 %, calibration via p0342) when the I component of thespeed controller (r1482) does not change during a ramp-up or ramp-down in therange n > 20 % * p0310. Thus, the pre-control allows a new speed setpoint to beapproached without overshoot (prerequisite: the torque limiting does not act andthe moment of inertia remains constant).If the speed controller is pre-controlled through injection, the speed setpoint(r0062) is delayed with the same smoothing time (p1442 or p1452) as the actualvalue (r1445). This ensures that no target/actual difference (r0064) occurs at thecontroller input during acceleration, which would be attributable solely to the signalpropagation time.When speed pre-control is activated, the speed setpoint must be specified continuouslyor without a higher interference level (avoids sudden torque changes). Anappropriate signal can be generated by smoothing the speed setpoint or activatingthe ramp-function generator rounding-off p1130 – p1131.The starting time r0345 (T start ) is a measure for the total moment of inertia J of themachine and describes the time during which the unloaded drive can be acceleratedwith the rated motor torque r0333 (M mot,rated ) from standstill to the rated motorspeed p0311 (n mot,rated ). 2 n mot,rated2 p0311r0345 T start J p0341 p0342 60 Mmot,rated 60 r0333If these basic conditions are in line with the application, the starting time can beused as the lowest value for the ramp-up or ramp-down time.© Siemens AG 2006 All Rights ReservedSINAMICS S120 Function Manual, 03/2006 Edition3-133