Communication Time Optimization of Register-Based Data Transfer

The data exchange according to communication protocols used in automation is often based on registers (e.g., Modbus). Values of many variables can be sent in a single frame, provided that they are placed in adjacent registers. If the required registers are not adjacent, it may sometimes be advantageous to transmit more registers than required, along with redundant ones, to minimize the number of frames and the total transmission time. The article analyzes the possibilities of improving time parameters and determining the optimal grouping based on the arrangement of registers. Various existing optimization approaches such as mixed integer linear programming, constraint programming, and a tabu search are analyzed, and several new simple deterministic algorithms (greedy or heuristic rule-based) are proposed. The results obtained were confirmed experimentally.