Research On Key Technology Of Soft Starter Communication Interface Based On Multi-protocol Of Fieldbus

Soft Starter is a kind of equipment which is used to control the motor starting and realize the motor smoothly start. Soft starter can reduce large current impact on the grid during the motor startup and increase motor life. Therefore the motor soft starters are applied to industrial control field extensively. Fieldbus automation control technology as an integral part has become an important way of industrial control. The last decade, with the various types of fieldbus protocol development, fieldbus products are launched. Compared with other protocols, Device Net, CANopen, MODBUS, PROFIBUS-DP are widely used. Currently, the number of soft starter products with communication interface is relatively small. And mostly, they have single fieldbus interface, and can only access to a kind of field bus network. Given the demand for different types of fieldbus products and the actual condition of industrial field, this topic designs a kind of soft starter communication interface based on multi-protocol of field bus. The communication interface can realize the three kinds of communication protocols, Device Net, CANopen and MODBUS. And the communication interface can access to the corresponding network and achieve function of network control. Communication interface of soft-start based on multi-protocol for the promotion of the development of the soft starter is significant.Firstly, this paper introduces the Device Net, CANopen and MODBUS field bus protocol. Then combined with the soft starter, the system hardware design scheme is proposed. The framework consists of SCM with integrated CAN controller, CAN bus transceiver, RS485 drive. STM32F103C8T6+CTM1050+MAX3485 as the core of the system hardware design solutions have been proposed. Software design solution is proposed for soft starter communication interface. Three kinds of protocol stack are transplanted to STM32 microcontroller. However in aspect of improving reliability of communication interface, the specific solutions of data security and dealing with network breakdown is proposed. And corresponding network communication function can be chieved.Finally, the soft starter communication interface laboratory experiment and field experiment are completed. In the laboratory, Device Net, CANopen, MODBUS network experimental platform was set up. Nextly Device Net, CANopen device EDS file of soft starter is written, and the soft starter communication interface network communication experimental is completed. The soft starter embeded communication interface is tested in the industrial field. Through the experiment and analysis of experimental data, the correctness of the soft starter communication interface is verified and the design proposed by this paper is proved stably and reliably.