Development Of Re-melting Control System Based On Infrared Temperature Measure Technology

Re-melting Control is used in the alloy powder coating's re-melting process on sucker rod couplings. The coating's temperature is measured by infrared temperature measurement device, then controls the sucker rod coupling's rotation and forward movement, and realizes automatic control of re-melting process. The achievement of re-melting automatic control system is of great practical significance to guarantee the re-melting coherence of sucker rod coupling's coating and improve the qualification rate.The existing coating re-melting technology, the features of high frequency induction heating technology and infrared temperature measure technology have been analyzed and studied. According to coating material characteristics, appropriate infrared thermometer is used in contactless temperature measurement for the coupling's coating. A control strategy aimed to achieve the coating's re-melting has been presented that considering temperature parameters, step motor movement and high-frequency induction heating device's start-stop operation. A re-melting distributed control model based on DCS structure has been designed. Using a single-chip SOC processor, systematic structure has been designed for direct control level were completed,.The temperature measure model of sucker rod coupling's coating which was heated by high-frequency induction heating device, step motor's control algorithm have been studied in this thesis. Communication protocol between direct control level and process management level has been confirmed. Then according to structured programming method, the application software for direct control level was developed using C language. Meanwhile, to guarantee the stability of system, many anti-interference methods in hardware and program algorithm were respectively adopted.A lot of practice examinations were done in the workshop. The examination results indicated that eligible rate of coupling products is improved more than 10% through using this system. And the rationality and validity of the system and its control method have been checked out. In the period of system examination, more than 11000 couplings were re-melted. Stability and reliability of the system have been proved.