System for accurately controlling dissolved oxygen content in water and use thereof

Abstract

The invention relates to a system and an application which can precisely control the content of dissolved oxygen in water. The system is composed of a dissolved oxygen sensor, a transmitter, a data acquisition module, a programmable controller, a signal outlet module, two proportional electromagnetic valves, and the like, the dissolved oxygen sensor can detect the content of the dissolved oxygen in the water, detected signals are integrated to 4 to 20mA analog signals through the transmitter, the analog signals are acquired to the programmable controller through the data acquisition module, the programmable controller calculates 4 to 20mA control signals according to the measured dissolved oxygen value and the set value, and the control signals are further transmitted onto the proportional electromagnetic valves to regulate the opening degree of regulating valves to control the type and the flow rate of the introduced gas. The system and the application can solve the serious lag and the unbalanced forward and reverse direction control of the controlled system through the optimization of the output range of the set forward and the reverse direction control signals and the proportion of the on-off time of the control signals, precisely control the (concentration or) content of the dissolved oxygen and control the precision to be within 5ppb.

Description

technical field [0001] The invention relates to a dissolved oxygen content control technology, in particular to a system and application that can precisely control the dissolved oxygen content in water. Background technique [0002] In chemical, food, pharmaceutical fields and laboratories, the content of dissolved oxygen in the reaction solution is often an important parameter that affects the production process or experimental results, so it is often required to strictly control this parameter near a certain set value. The dissolution and removal of gas is a relatively lagging process, which takes a long time to reach equilibrium, and the forward control process and reverse control process are not balanced, which brings great difficulties to accurately control the dissolved oxygen content. . The control effect obtained by the conventional PID control algorithm is not ideal, and it is difficult to meet the strict control accuracy requirements. Contents of the invention ...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a system for accurately controlling the dissolved oxygen content in water and its application, so as to solve the problems of hysteresis of the controlled system and unbalanced forward and reverse control processes.

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