Based on the CAN bus of the DNC remote diagnostics and monitoring system (1)

0 introduction

DNC (DistributedNumericalControl) is the workshop of CNC machine tools and host control computer integration to achieve processing equipment focus control and management.

This way, although to take full advantage of the potential of the equipment, improving the productivity of enterprises, but the equipment maintenance set higher requirements. Line key device long outages, will bring great losses of production. In order to make the loss to a minimum, should improve equipment reliability, processing equipment for status monitoring so that equipment failure symptoms, timely treatment, reduces troubleshooting and maintenance time. But from my most enterprises staffing patterns, Enterprise for equipment maintenance technicians with a relatively small, it is not possible throughout the establishment post-sale service center, when equipment fails, due to geographical reasons experts cannot arrive on site failure, also could not understand the device at the time of actual operating conditions and the basic parameters of the scene, not only to diagnose difficult also gives users a huge economic losses. This paper presents a can-based remote diagnosis and DNC supervisory system, and on its architecture and implementation of key technologies.

1 system architecture

Based on the CAN bus (TheControllerAreaNet-workFieldbus) DNC remote diagnostics and monitoring system is mainly composed of DSP data collector, host monitor, database servers, Enterprise Web server, Enterprise fault diagnosis Center and remote diagnosis Center 6 parts, as shown in Figure 1.

DSP data acquisition from sensor Group acquisition signals from CNC machine tools (such as from a tool cutting vibration signals, machine tool spindle bearings vibration signal, the temperature of the hydraulic system, etc.), and a series of signal processing (such as voltage filter and A/D conversion), via can bus into upper monitoring machine (another backup redundant monitoring machine).

Upper monitoring with real-time online monitoring system not only to achieve real-time data display, real-time data storage, but also through WinSocket control to communicate with the database. In addition, the upper monitoring machine can also be based on the device's processing capacity will be processing through CAN bus/RS232 and CAN convert module into different numerical control machine to complete parts; database server installed Microsoft SQLServer2000. Database server the application's main task is receiving and processing from the upper monitoring machine data, and the received data is written to the buffer, the original data in the data analysis process after it is written to the SQLServer database. When a line of a machine failure, at fault time records will be written to the device fault condition table; the Web server is set up the services on the Internet site, corporate fault diagnosis Center and remote diagnosis Center with Web servers using b/S (browser/server) mode, all the monitoring, analysis, Diagnostics software are placed on a Web server, and are managed by Web home page.

2 remote diagnostics and monitoring system

2.1 on real-time data acquisition

This remote diagnostics and monitoring system in the field device-level communications program sets some low-level functions for upper monitoring machines calls for DSP collector and monitoring machine communication.

Live real-time data collection workflow is: sensor signal after a necessary regulator filter, into the ADC (analog to digital converter), and in accordance with the data of different needs, if reference, information signals, data storage like the right time to the PC; if it is more urgent and immediate control feedback data, such as machine alarm signal, it is timely delivered to the host computer to be processed or used as a control. System, the DSP chip alone, and complete the data collection. And PC download data table flexible change sensor calibration coefficient, is particularly suitable for sensor linearity is not a very good system. The DSP work status and operating mode by the host computer to keep and improve the system's adaptability.

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