BIT PROCESSOR WITH POWERS FLOW REGISTER SWITCHES CONTROL A FUNCTION BLOCK PROCESSOR FOR EXECUTION OF THE CURRENT COMMAND

摘要

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 adjusts the instruction pointer to point to the next OPCODE in the user program memory.