Study Of Control System Of Lighting Inspection Machine

Plasma TV is a high-tech TV using plasma display technology. Being one of the outstanding panel display performers, PDP has many advantages such as high contrast, high image response speed, wide angle of view and wide working temperature. PDP production is a complex process, and the test of panel's display effect is a key step in the panel production. The topic researched in this paper, which comes from Sichuan Changhong Group's PDP production project, is that researching a device called PDP Lighting Inspection Machine to test the display effect of PDPs.PDP Lighting Inspection Machines locate on the PDP production line, which apply TV signal to PDPs through programmable power supplies and test the electrical and optical information of them. This machine is consisted of a color analysis system and a control system based on PLC. The PLC control system controls the transfer of PDPs between PDP Lighting Inspection Machines and conveyor, executes visual positioning and links TV signal through electrodes to PDP. This paper considers the PLC control system. The machine's action workflow is designed. Multi-layer network is built to connect with the whole production system and peripheral equipments's usage is researched. Optional operation modes are designed and Man-machine interface is introduced to facilitate the operation.Firstly, the machine's structure and the moving parts are introduced in this paper. And the machine's operation modes are designed, which includes Automatical mode, Semi-Automatical mode and Manual mode. Different sensors detect the PDP's position to links mechanical actions in Automatical mode. In Semi-Automatical mode, operators load and unload panels manually and the machine completes the rest job. Manual mode is usually used for debugging for all the actions can be accomplished individually.Next, the control system's network is designed, which has 3 modes. The first one is an Ethernet module linking to Manufacturing Execution System (MES), which receives information from production system and sends production information to MES. The second one is a MELSECNET/H network linking to the production line, in which the signal is used to transfer PDPs between conveyor and the machine. The third one is a CC-Link network managing the I/O signals, which is the machine's internal network.The PLC control system connects a controller of visual positioning through serial port. A whole workflow is designed by sending and receiving serializing instructors to accomplish the visual positioning process. An Ethernet module links PLC and upper PC to transfer information between the PLC control system and the color analysis system. What is more, a touch panel is introduced to work as human-machine interface. The operation of the machine, the monitoring of the system and alarm processing are completed on the touch panel.Last, the whole system is summarized and several constructive proposals are offered.