Design and Application of Queue-Buffer Communication Model in Pneumatic Conveying

In order to communicate with a PLC (Programmable Logic Controller) flexibly and freely, a data communication model based on the PLC's free port is designed. In the structure of the model, a distributed data communication environment is constructed by using Ethernet and serial adapters. In the communication algorithm, a method of queuebuffer for multi-threaded is used to improve the real-time of the control. This communication model has good scalability and portability because the realization of it is not restricted by the number of PLC slave stations and the type of operating system of the host computer. A corresponding communication algorithm is applied to data collection and devices monitoring for a pipe pneumatic conveying system. The practice shows that not only the stability and reliability of the model can meet the needs of automatic control but also the communication performance and efficiency of the model is outstanding. Keywords—Queue-Buffer; Programmable Logic Controller; Freeport Communication; Critical resource; Mutex