Abstract: The present invention discloses a new data collection method employed by a middle layer between the host and the equipment, which improves the speed and consistency of data collection. The middle layer incorporated with the proposed data collection method functions as a data format converter as well as a data processor/classifier, which helps to filter and format messages before delivering data to the host or equipment. The proposed data collection method enables the middle layer to perform local reply, local data sampling, and group data polling, thus relieving processing resources of both the equipment and the host. This allows implementation of APC on older wafer fabrication processes using old equipment.