Clamp control for injection molding machine

A method for controlling the molding cycle of an injection molding machine having a plurality of controls, each control regulating one or more states of the molding cycle and a change in the output of any specific control representing a state transition indicative of the progression of the molding cycle through a specific phase of the molding cycle, the method comprising the steps of:

• a) initially evaluating a first set of normal equations by means of a programmable logic controller periodically scanning said first set of equations;
• b) generating a variable control signal for each control indicative, upon variation, of the occurrence of a sensed event during the molding cycle;
• at least one variable control signal for one specific control evaluated by said programmable logic controller performing said first set of normal equations and generating an output signal for actuating said control upon the occurrence of a change in said variable control signal;
• c) evaluating a second set of normal equations in lieu of said first set of normal equations when said first set of normal equations evaluated by said programmable logic controller causes generation of said output signal for actuation of said specific control whereby said state of said molding cycle is changed;
• and
• d) sequentially evaluating subsequent sets of normal equations in lieu of previously evaluated sets of normal equations once a specific variable control signal causes the programmable logic controller performing sets of normal equations associated with that variable control signal to generate an output signal to, in turn, change the output of the control associated therewith until the molding cycle is completed whereby the scan time of said programmable controller is reduced and the response time of the control is increased.