Figure 1 shows a typical winding setup. This setup can be used for a host of different winding applications. The waveforms as shown in figures 2 & 3 dictate that as the shuttle moves back and forth, the speed of the spindle increases and decreases accordingly in order to facilitate faster thruput. Since the shuttle cannot reverse directions at maximum velocity, the imposed accelerations and speeds are selected to facilitate the correct winding relationships to prevent "dog boning" at the ends of travel. The following explanation of this application shows how this is solved with one of the many intelligent controllers from Baldor Electric.

Using an electronic cam function solves this particular problem. By calculating distances using the desired velocities and times required to reach them (see figure 2), and then converting the distances to encoder counts, we are able to build a cam table of points with associated master increments (MASTERINC) as shown in the Mint code listing later in the text. For this article, we are assuming that there are 4000 encoder counts per revolution of the spindle and 4000 (two revs @ 2000 encoder counts) of the shuttle. (See figure 1)

In cam profiling, for a given move on the master, the slave will move a pre-defined distance "position locked" to the master. To create the software cam, the cam is broken down into discrete linear moves or segments. These moves are then linked with the master axis such that the slave will move the specified distance for a measured move on the master thus creating a software gearbox. By placing the defined points in a table, (see DIM CAM0(9) in figure 5) allows Mint to execute the cam in background. A cam segment can be given in either relative or absolute positions. Either the CAM or CAMA keywords will determine the actual move. The MASTERINC keyword is used to determine the distance over which the slave (the cam) will move over. For a cam table, MASTERINC applies to each cam segment in the table. If different MASTERINC values are required for each individual cam segment, the master increment values can be defined in a table (see DIM MINC0(8) in figure 5), where the table is a standard Mint array.

The Shuttle (as axis 0) will follow whatever the Spindle (axis 1) does by using the command: FOLLOWAXIS.0 = 1. Using the expression: CAM = 1 (a relative cam which is executed continuously) imposes whatever is contained in the cam table defined for axis 0. By defining a master increment table, the MASTERINC value allows the cam points to be expressed over different distances which are dictated by the timing diagram.

NOTE: there are several ways in which a cam can be executed as shown in the table below.