Software for the synchronization of axes - Kollmorgen

SOCAPEL SA SOFTWARE FOR SYNCHRONIZATION OF AXES 024.8068.A8.8 PERIODICITY8.8.1 Periodic ModeMotor-driven axes can be classified as belonging in one of two categories- axes having a limited degree of travel : for example, a machine-tool bed;- axes having an unlimited degree of travel, in most cases operating in a singledirection : for example, printing-press cylinder; conveyor belt; cutting-tool headetc.The latter types of axes include the notion of "periodicity" : motor revolution, cylinderrevolution, space between cars, chain links etc. With these axes, there is no point insynchronizing the slave shaft with the original position of the master shaft : the positionof the latter might be far-distant if the slave has been operating out of synch for a longperiod. Hence synchronizing is performed using the nearest period.The earlier discussion concerning relative positioning of the master and slave shaftsintroduced the variable PMUS for the master and the variable INTV for the slave. Thenotion of periodicity can now be introduced, in the form of two new variables, MOMUSand MOPHI. MOMUS contains an integer value that is the closest expression of thenumber of counted periods contained in PMUS.PMUSPeriodicityMOMUSPositionFigure 8.11More precisely, MOMUS follows PMUS at a distance of one period at the most. Asimilar arrangement exists between MOPHI and INTV. Thus when synchronizing isrequired, the difference taken into account is not that between INTV and PMUS, butrather that between (INTV-MOPHI) and (PMUS-MOMUS).This notion of periodicity can be applied at the master or the slave, or both. Themaster and slave periods can be equal or different : the choice is made in the"periodicity" parameter groups.When the system increments MOMUS by one period, bit 2 of STATC is set to "1". Thisbit can be used by the sequencer to trigger a sequence.75