Programmable logic controller including a function block processor and a bit processor

Abstract From the Canadian patent

A programmable logic controller is provided which includes a function block processor for processing function block instructions and a bit processor for processing Boolean instructions. The bit processor decodes and identifies the OPCODE of each instruction command in a user program memory and returns control to the function block processor if at least one of the following two conditions occurs namely, 1) there is power flow in the power flow register of the bit processor and 2) the function block is one which must be executed by the function block processor. The bit processor waits until the function block processor has retrieved the instruction pointer from the bit processor and then …