Modifying tables with motion segments

Online modification of tables with motion segments (zebra tables) is done directly in the table memory (shared memory) because the kernel only works with a copy of the active cam table. As a maximum of 360 master and slave values pairs in the SGN32 format can be defined for each table, the internal memory requirement is only 2880 bytes.

The modified table is activated by commanding MC_CamIn again. If possible, the table should be switched over in a safe area in which the slave is not moving (LINE with 0 speed). Despite standstill of the slave, synchronization to a new table requires a phase of synchronization to speed (equal to 0) and balancing of the phase position. This operation can take a few cycles depending on the setting in the axis MDS. Presuming that the slave is not moving and does not have to perform phase compensation (characteristic of the safe range), synchronization to the cam table will be completed in the time set in the axis MDS for dwelling within the speed window (usually for about 20 to 30 ms). If the slave is synchronized at standstill and the dwell time has already elapsed within the speed window, optimization might have to take place here to ensure that the entire operation is completed in only a few cycles.

The range in which the slave is resynchronized should be of the LINE type because only then is there a guarantee that the speed is constantly equal to 0 throughout the interval. In the case of a polynomial, this will generally result in movement of the slave.