Abstract: A multi-operation control system is made up of a plurality of slave computers at least some of which are axis computers each monitoring its respective operation and receiving instructions broken down into plurality of discreet actions. The current state S.sub.c,N of each slave is determined and is compared with preset absolute maximum status for that slave S.sub.ab,N(max) and the maximum acceptable change in status .delta.S.sub.a,N(max) of each respective slave is determined and the corresponding appropriate state signal based on the maximum acceptable change to that slave is sent to all of the slaves in the system. Each axis slave then reads all state signals and determines the highest state signal acceptable to all slaves and each axis slave then carries out its correspond increment(s) of change in status .delta. S.sub.N based on the highest S.sub.a,N(max) acceptable to all slaves.

Abstract: The desired path for each axis is predefined and converted to a first series of coarse position increments at time intervals. The coarse position increments are converted to a second series of spaced, (in time), fine position increments and expected values of velocity v. The latter parameters requiring splining and interpolation of values. The actual position of each axis is measured and compared with that required (by the fine series of position increments) to determine the resulting error E which is then compared with a calculated allowable error, e.sub.allowable calculated as a function of the then current planned velocity value v i.e. the planned value of velocity v corresponding to the current fine position increment and a signal is triggered when the actual error E exceeds the allowable error e.sub.allowable to prevent processing of the next increment in the second series of increments.