Design And Development Of Cylindrical Tank Automatic Spraying Device Control System

Large cylindrical tank is common storage equipment in oil, chemical, aerospace industry. Most enterprises are using the manual spraying which is a less-automated method. The manual spraying not only make uneven coating and low efficiency defects, it will also do harm to the health of workers. Nowadays, with further increase of large tank demand, designing a low cost and high efficiency automatic spraying device control system has a very important significance.Aiming at the high quality requirements of the large cylindrical tank paint-coat and the difficulties of the surface spray coating, through understanding the situation and development trends of automatic spraying system and combined with the actual production requirements of spraying, an automatic spraying system based on programmable logic controller(PLC) was proposed, hardware and software of the control system were designed and developed.The structure of this spraying system is made up of A axis, driving cylindrical tank rotating, X, Y, Z axis, driving spray gun’s space motion, C axis, driving spray swing, frame and the support mechanism. System adopted SIEMENS S7-300 PLC connecting FM357-2 position control module as the core, used MITSUBISHI servo drivers and servo motors as driving units to control X, Y, Z, A, C axes, employed the SIEMENS MP 277 touch screen to transfer information through the PROFIBUS communication protocol. The system used the modularization thinking to design main spraying control module, automatic spraying module, manual spraying module, reset module and parameters read&call module. These modules were programmed under the STEP7 and FM357-2 parameterization tool development environments. Aiming at the Spiral Spraying of the tank-body and the Contour Spraying of the bottom surfaces, the corresponding NC control procedures were developed. Human Machine Interface of the system adopted the WinCC flexible configuration software to design the main control interface, parameters setting interface, alarm interface and etc, thus realized the system configuration, data acquisition, data process, display and control. Through setting tank parameters, the system developed the spraying trajectory control points algorithm using Visual Basic Script. The results of the study show that, the system can spray different sizes of tanks automatically. The problem of uneven coating and low efficiency of manual spraying work were solved.