1.The introduction
    Since entering this century, the world's energy supply tensions, rising oil prices.China and the world within the scope of the great development of energy industry, promote the great development of petroleum machinery industry.At present, all kinds of field bus technology has been widely used in the industry, providing favorable conditions for the development of the industry.In this paper, a large petroleum machinery project, Siemens S7-300 PLC on PLVC (valve with programmable controller) to monitor implementation of the proportional valve control.In the whole control system, see bo automation turn CANopen PROFIBUS DP gateway PCO - 150 s showed the advantages of stable and reliable.

2.System composition
    This system structure as shown in figure 1, which omits the field level except the Siemens S7-300 PLC control equipment.Siemens S7-300 PLC is one of the main tasks of the PLVC (valve with programmable controller) surveillance to control the action of the proportional valve.Siemens S7-300 PLC (CPU models: CPU313C - 2 DP) using PROFIBUS DP master station agreement;PLVC (valve with programmable controller) is used widely used CAN bus technology, the car industry as CANopen master station, proportional valve control site.In the project, in order to achieve the Siemens S7-300 PLC and HAWE PLVC two-way transmission of data, adopted see bo automation of high-performance CANopen from standing PROFIBUS DP slave station gateway PCO - 150s: