Design Of Measurement And Control Equipment For Natural Gas Door Station Based On Multi-master Redundant Communication Network

With the rapid development of the national economy,intelligent instrumentation has gradually replaced traditional mechanical pointer meters,which has promoted the rapid development of automation in the field of natural gas measurement and control.In the Station Control System,such as the natural gas gate station and the regulator station,the signal quantity is mostly based on 4-20 mA analog signal and non-bus digital quantity.At least 2 signal transmission lines are required for each analog device,and 3 signal transmission lines are required for each non-bus-type digital quantity.Therefore,with the increase of measurement and control points,the signal transmission lines which are from the site to the control room will increase exponentially.Because of its distance ranging from tens of meters to hundreds of meters,the building period of the cable will be longer and the cost will be higher.The system's installation and post-maintenance will be more difficult,and at the same time,the stability of the system also will decline.In view of this,this article has proposed using the field bus to replace the original method of data collection and transmission,so as to reduce the number of cables.In the Station Control System of natural gas,Ethernet is commonly used as the only way of transmission between the host computer and the field control system.If the only way of transmission(Ethernet or the field bus)fails,the data transmission will be interrupted directly,and the field control system will not be monitored in real time,it may cause inestimable damage to the local area.In this regard,a set of wireless redundant communication methods are provided to Ethernet and field bus respectively in the paper,to ensure that the system will use corresponding redundant wireless communication when the wired communication is abnormal.In the whole design and development process,first we studied and analyzed the current situation at home and abroad,and then chose STM32 as MCU,and appropriate communication chip and its corresponding peripheral chips according to the function needs.The circuit schematic and the design and production of PCB were made by using Altium Designer.Then we designed and wrote MCU software with Keil-MDK.With QT5.8 as the platform,the host computer communication parameter configuration software was designed and developed to provide the parameter modification method without code update and download.Combined with the above methods and steps,a complete set of double redundant communication devices was designed and developed.The field bus used in this article is a CAN bus,and the two types of wireless communication is GPRS communication and ZigBee communication respectively.Ethernet and GPRS communication form redundant communication,and CAN bus and ZigBee form redundant communication.The designed redundant equipment includes two types of modules: a gateway module and a terminal module.The tests showed that the double redundant communication measurement and control equipment realized that the switching of the autonomous communication mode,which ensured that the uninterrupted transmission of data between the host computer and the filed.