Parker Hannifin S.p.A S.B.C. Division SLVDN User’s ManualPage 163 of 181Figure 17, Figure 18 and Figure 19 show the difference between the "set of set-points" modeand the "single set-point" mode. The initial status of the bit ‘change set immediately’ in thecontrolword determines which mode is used. To keep simple these examples, only trapezoidalmoves are used.If the bit ‘change set immediately’ is "0" (continuously drawn line in Figure 17) a single set-point is expected by the drive (1). After data is applied to the drive, a host signals that the datais valid by changing the bit ‘new set-point’ to "1" in the controlword (2). The drive respondswith ‘set-point acknowledge’ set to "1" in the statusword (3) after it recognized and bufferedthe new valid data. Now the host may release ‘new set-point’ (4) and afterwards the drivesignals with ‘set-point acknowledge’ equal "0" its ability to accept new data again (5). InFigure 18 this mechanism results in a velocity of zero after ramping down in order to reach atarget position x1.at t1. After signaling to the host, that the set-point is reached like describedabove, the next target position x2 is processed at t2 and reached at t3.Figure 18: Single set-pointIf the bit ‘change set immediately’ is "1" (dashed line in Figure 17) the new target positionwill be active immediately. In Figure 19 the drive receives the first target position at t0. Atthe time point t1 the drive receives a second target position. The drive readapts the actualmove to the new target position immediately.Figure 19: Change set immediately13.1.9.4. Functional descriptionFigure 33 shows the meaning of the sub-function position reached. Symmetrically around thetarget position a window is defined for the accepted position range. If a drive is situated in theaccepted position range over the time position window time the bit target reached (bit 10) inthe statusword is to set.
