Wireless distributed sequence control system was proposed based on the background of the sequence control for the ultrafiltration system in chemical water treatment in power plant. The most prominent features of this system are that there is no centralized controller and control logic is executed in distributed wireless nodes. The control task was mainly fulfilled by the wireless nodes belonging to the field control level and the states of the devices are transmitted through wireless network totally. So the model of wireless distributed sequence control system using Petri nets was constructed to analyze the delay and bit errors in wireless transmission. And the method of state restriction was proposed to enhance the correct operation and the deviation compensation was introduced to minimize the deviation of the duration of the states. At last, the comparisons of the simulation result show the effectiveness of the designed approaches.

Time synchronization technology is an important part of wireless sensor networks. Many applications of wireless sensor networks are built on the basis of an accurate synchronized timing. Compared with other typical time synchronization algorithms,flooding time synchronization protocol(FTSP) is the most effective method. It considers the time synchronization accuracy,power consumption,scalability and robustness,but doesn't pay attention to the fault tolerance. This paper brought in the residual analysis to find the abnormal information received by nodes and gave it an error judgment. In addition,the estimated clock drift rate was revised. The simulation results show that the improved algorithm not only has good fault tolerant ability to error messages,but also implements high synchronous accuracy and stability.

As the performance of the wireless sensor networks is sensitive to the environment of the application, the analysis of wireless channel is carried out in the workshop of the chemical water treatment in power plant. With the power of noise and received signals sampled, the path-loss exponent γ is derived to establish the model of the wireless channel. To meet the requirement of the performance of wireless communication, such as a given bit error rate (BER), the upper bound of the distance between transmitter and receiver is also presented. At last, the conclusion is given.