Abstract: Rapid development of control programs for programmable logic controllers controlling semi-standard combinations of equipment is provided by the creation of relay ladder logic objects prestored in the programmable logic controller and invoked only as needed for the particular application. The inability of a programmable logic controller to provide for the memory management mechanisms necessary for true software object instancing is overcome by pre-storing the objects in the programmable controller with pre-allocated variable addresses. Connection of the used objects to I/O is provided by a mapper program also written in relay ladder code. The objects are associated with particular pieces of equipment and provide inter-machine control for that equipment while high level control program executed on a standard computer which controls the objects through reading and writing of object variables.

Abstract: A controller for controlling a pellet mill, used to extrude milled ingredients through a die into more manageable and economical pellets, keys particular control parameters to a library of pellet types and then adjusts the control parameters to optimize throughput within the limits imposed by potential plugging of the die. If a potential plugging is detected, the controller responds in two stages, intended to reduce the restart time for pluggings of less severity, and thus to allow more aggressive operation. Pellet fines are recycled and liquid ingredients compensated to provide improved efficiency.

Abstract: A controller for controlling a pellet mill, used to extrude milled ingredients through a die into more manageable and economical pellets, keys particular control parameters to a library of pellet types and then adjusts the control parameters to optimize throughput within the limits imposed by potential plugging of the die. If a potential plugging is detected, the controller responds in two stages, intended to reduce the restart time for pluggings of less severity, and thus to allow more aggressive operation. Pellet fines are recycled and liquid ingredients compensated to provide improved efficiency.