GAS MIXING CONTROLLER AND METHOD FOR CONTROLLING MIXING RATIO IN GAS MIXING CONTROLLER

摘要

Disclosed are a gas mixing controller and a method for controlling the mixing ratio in the gas mixing controller. The present invention comprises the process of: a gas mixing controller transmitting respective target flow values, determined according to target mixing ratios, to a plurality of mass flow controllers (MFC's) which respectively control the flows at a plurality of pipes; receiving respective actual flow values from each outlet of the plurality of pipes through the plurality of MFC's; revising target flow values for MFC's controlling the flow from the remaining pipes of the plurality of pipes which are not pipes for which the difference between the target flow value and the actual flow value does not lie outside a predetermined error range; and receiving the revised target flow values through the MFC's controlling the flow for the remaining pipes. According to the present invention, the target flow for an elemental gas is actively readjusted so as to prevent the occurrence of a mixing ratio error in the gas mixture which occurs due to an error in the flow of the elemental gas.