Traditional PVC floor detecting is done by workers’ handwork, which is hard and inefficient. So studying and designing a set of control system which is based on PLC for PVC floor detecting conveyor device. The PVC floor detecting conveyor device consists of loading, conveying and unloading and other parts. To make the whole system works in a coordinate and controllable status. Firstly, by using double layer hydraulic scissors lift to realize the lifting and stratified translational control of lifting platform; secondly, with the use of photoelectric switches, counters and other components, station transport algorithm helps the process of PVC floor detecting conveyor; Finally, according cutting control requirements of stacker, the PLC auto-control and speed optimization can be done by layered multiple stacking. Thus automated loading, conveying and unloading process are come true, greatly reducing the labor intensity and improving production efficiency. Introduction With the quick development of economy and technology in china, computer technology, microelectronic technology and automatic control technology has also been rapid development, especially the programmable logic controller (PLC) technology has entered a new age. It has a simple and convenient programming, strong control functions, easy to implement mechatronics and other advantages. At present, many domestic and foreign scholars use PLC in machinery manufacturing, iron and steel, petroleum, chemical, textile, building materials and other industries. PLC technology was used in document [1] to control conveyors and sorting machines, which realizing the sorting and transmission for large and small balls; A five degrees of freedom ingredients manipulator which based on PLC was developed in document [2], the manipulator used PLC as the control core and a control technology combining electrical control and pneumatic control, realizing various functions of the cup action required in automatic batching process. Document [3] showed that PLC system can be used to realize the control of temperature in the design and construct of heating system. Additionally, A rapid and economical manufacturing method was developed in document [4], which combining PLC module and three-axis CNC milling machine to manufacture spiral bevel gears. Existing PVC floor detecting is done by workers’ handwork, which will cost a lot of labor and time. Therefore, a kind of PVC floor detect equipment is designed in this paper, including hydraulic double scissor lift, conveyance system and stacker. This paper utilizes PLC, combined with trip switches, photoelectric switches, counters and other component, to design the control system for PVC floor detecting and conveyance device, making it an effective control for the process of PVC floor’s loading, conveying and unloading. So, this detect equipment can achieve rapid and efficient detecting for the PVC floor. Detecting Process of PVC Floor The specification of PVC floor is 200mm1210mm, 5mm thickness, 2.3kg per piece, PVC floors to be detected are placed on a layer board, there are four piles of PVC floors on the layer board and each pile has 160 PVC floors. PVC floor detecting process is divided into flare detecting and flat detecting which shown in Figure1. Figure 1. Schematic diagram of PVC floor detecting. Schematic diagram of PVC floor detecting is shown in Figure 1. The specific structures include pneumatic lifting plate1, operator 2 and 10, conveyor belt wheel 3, photoelectric switch 4, 7 and 12, lifting plate with air cylinder drive 5, roller bed with mot or drive 6, positioning baffle 8, 9, 11, and 14, unloading stacker 13, lighting 15, waste station 16. There are four pile of PVC floors waiting for being detected in the hydraulic lifting platform 1, flare detecting is done by operator 2 in the front of the hydraulic lifting platform 1. The floors were put on the belt 3 to convey after the flare detecting. It will be delivered to the lifting plate 5 by conveyor; Lifting plate is driven under the action of the cylinder’s moving up and down. When the number of PVC floor through the light sensor 4 reaches 16, counter displays and transmits digital signal 16, pneumatic piston back, lifting plate 5 drops, PVC floor is transported to positioning baffle 14 at the action of roller bed 6. At the time of the PVC floor goes through the light sensor 7, pneumatic piston out, and lifting plate 5 rises. The operator 10 starts the flat detecting (rollers in front of the operator 10 are used for flat detecting, without a motor drive), waste is placed on the waste table 16. After detecting a stack of floors are transported to positioning baffle 11 under the action of roller bed 6, light sensor 12 passes signal to unloading stacker 13, unloading stacker 13 begins to unload. Control System Design for Hydraulic Lifting Platform Loading Control Requirements for Hydraulic Lifting Platform Hydraulic lifting platform is the overall moving scissor mechanism [5][7], It can not only move up and down, but also can move back and forth. The control process can be achieved manually, and can be automatically run as well. In the initial state, there are four pile of PVC floors on the hydraulic lifting platform. For ease of operation in detecting and loading, the hydraulic lifting platform is placed 1 meter below the horizontal plane. Firstly, the operator carries out flare detecting with the PVC floor which is nearest to the conveyor belt then loading floors to conveyor belt. If the thickness of PVC floor is half of each pile, about 80 pieces. The operator controls the hydraulic system with buttons to enable the lifting platform advancing some distance to the conveyor direction; he loading the second pile of PVC floors next, the loading thickness on the conveyor belt is as same as the first pile, then he secondly controls the hydraulic system with buttons to enable the lifting platform advancing some distance. At this time, the advancing part of the lifting platform extends below the conveyor belt directly; Then after the operator loads the third and fourth pile of PCV floors like the above method, in this time the operator presses the button to control the lifting platform back to the starting position and increase the height of platform, then the operator loads the remaining first pile of PVC floors, in accordance with this order, the loading process will be finished finally. I / O Assignment and Hydraulic Principles Mitsubishi PLC FX2N-32MR is used in control process to design lifting platform control system. I/O assignment and wiring principle of hydraulic lifting platform is shown in Figure 2.