Temperature Control Of Three Section Blackbody Furnace Based On PLC

As the standard radiation source, the stability and isotherm of the blackbody furnace affect the accuracy of various radiation thermometers directly. Now, the temperature of blackbody furnace is controlled by manual, which is subjective. This paper designs the temperature control system of three section blackbody furnace. The system guarantees the uniformity and stability of the blackbody cavity and makes it meet the practical requirements.The main contents of this topic are as follows:(1) Build an automatic temperature control system of blackbody furnace. This process includes analyzing the control system requirements; choosing the way of temperature control, temperature control algorithm and control devices; improving the original circuit to enhance the organization and reliability of it.(2) Design an incremental PID controller. According to the characteristics of the blackbody furnace, the paper improves the PID controller. And the designing includes subdivision control, restricting integral increase quantity; dealing the data by moving average filtering. The control process adopts the pattern that from low temperature to high to control temperature. And do the actual debugging.(3) Design a single neuron self-adaptive PID controller. In order to improving the self-adoption ability of the system, this chapter proposes single neuron self-adaptive PID algorithm. According to the parameters of single neuron self-adaptive PID controller corresponding to parameters of PID controller, this paper provides a group of neurons vector parameter. At last, author debugs the new algorithm, compare the self-regulation, anti-interference and control accuracy.Experimental results show that the two algorithms for temperature control both meet the actual demands. Though the anti-interference and precision of the single neuron self-adaptive PID controller are lower than that of the conventional PID controller, which the applicability is stronger when object properties change, and the parameters of the single neuron self-adaptive PID controller are easier to set. After applying this control system on three section blackbody furnace during 1500℃, we can acquire such effects:(1) Stability:temperature difference among three section that is ΔTmax<1℃;(2) Overshooting:σ%≤1%;(3) Uniformity:the temperature of radiation cavity is uniformity, at the bottom of the cavity, within 100 mm along the horizontal direction, the change of the temperature is<2℃.