Elmo HARSFEN0602, HARmonica software manual 135, Example

HARSFEN0602ElmoHARmonicaSoftwareManual PRELIMINARYDRAFT

135

The largest PTP motion available is XM/2 (or 230 if XM=0). This is since with modulo calculations, the PTP motion will always go the short way. For example, if XM=1000, the present position reference is 490, and the command PA=-490;BG is entered, then the position reference will increase and go through 499 to –500 and then to –490. The total length of the movement shall be 20 counts.

The parameters of PTP motion are summarized in the table below.

Parameter	Action
AC	Acceleration in counts/ sec2
DC	Deceleration in counts/ sec2
SP	Maximum speed in counts/sec
SF	Smooth factor, in milliseconds
PR	Relative position in counts
PA	Specifies that the next motion shall be a PTP, and the absolute target position.
	Table 12-5 – Parameter of PTP Motion

The PA command has more than one role. PA=n specifies that the next BG will start a PTP motion. In addition, it specifies the target of the next PTP move.

When in the PTP mode, a BG command performs the following algorithm: PA=PA+PR

•Go to PA

PA is the absolute position target.

PR is the relative position target. The PR parameter enables the specification of an incremental move, or a series of incremental moves. PR is reset to zero by the PA=n command. Therefore, PA=n; BG initiates a motion towards n.

The value of PA is incremented automatically with PR every time a new motion is initiated. For example, the sequence

PA=0;BG;while(MS==0);PR=1000;BG; while(MS==0);BG; while(MS==0);BG Initiates four consecutive PTP motions, targeted to 0,1000,2000,and 3000 counts respectively.

12.1.4.2Example

The simplest point-to-point motion is from a stationary position to another stationary position. The acceleration and the final speed limits are AC=100000,DC=200000,SP=2000.

We begin from PX=0 and command PA=70;BG

The speed graph shows the acceleration, constant speed, and deceleration state in the trajectory to the target.