Study Of Digital Self-examined Electro-hydraulic Servo System By PROFIBUS

As the research hotspot of the automatic control domain by now, PROFIBUS technology has already unceasingly unified with each industry domain, widely is applied to the industrial production. PROFIBUS technology has provided the extremely advantageous condition for realizing the intellectualization and the digitization of the control system in industrial production. This article takes PROFIBUS as tool, uses the hydraulic servo system as the research object, and proposes digital self-diagnosis electro-hydraulic servo system research plan based on PROFIBUS.This article has carried on the detailed analysis about the electro-hydraulic position- pressure servo system, according to the characteristic of the electro-hydraulic position-pressure servo system, combining with PROFIBUS technology, the network technology and PLC technology, has established the digital self-diagnosis electro-hydraulic servo system based on PROFIBUS. The main character of this system is: both of control module and monitor diagnosis module of the system adopt the integrative design; it takes Siemens S7-300 PLC as the digital controller of the system; The electro-hydraulic servo unit which the system used, is the digital electro-hydraulic servo unit, the servo amplifier is embedded in the electro-hydraulic servo valve; the data communication function of the system is realized by PROFIBUS technology.Combining with the typical electro-hydraulic position-pressure servo system, namely RD valve hydraulic servo system of the smoke purification recycling in the steel-making production, this article has mainly carried on the research about realizing the self-diagnosis function of the electro-hydraulic servo system based on PROFIBUS, has established the online control and monitor system based on PROFIBUS. According to the design request of the online control and monitor system, this article separately has carried on the system design from the hardware aspect and the software aspect. The key of the online control and monitor system's hardware configuration is the design of the PROFIBUS-DP intelligence substation hardware. This intelligence substation's exploitation uses monolithic integrated circuit + PROFIBUS which is special-purpose to ASIC hardware design. Thereinto, mainly designs 80C32 microprocessor interface circuit, RS485 & the PROFIBUS-DP interface circuit, the signal collection & process partial interface circuit. Based on the plan of the hardware configuration, the author has designed the special-purpose online control and monitor software. This control and monitor software mainly divides into control and monitor & diagnosis two parts. Using Siemens STEP 7 software, has exploited control program aiming at the hydraulic system, thus, has realized PID control on the electro-hydraulic servo valve. The monitor & diagnosis interface is constructed by WINCC configuration software. In this monitor & diagnosis software, exists very good interaction between the monitor & diagnosis part and the control section, can realize self-alarm and self-diagnosis functions.