Use of a programmable logic controller (PLC) for temperature, position, velocity and pressure control of injection molding machinery

The use of a PLC for close, repeatable control of all injection molding process variables, pressures, positions, velocities, and temperatures is described. Based on a distributed processing concept, this approach promises to provide fast, real-time open or closed-loop control of every injection molding process variable, while boosting productivity through optimized cycle times. This distributed processor concept is described in detail, with emphasis on the position, velocity, and pressure processor, the operator's panel, the temperature control processor, and the role of local area networks.<>