| With the development of automation technology, remote I/O devices graduallyreplace the traditional I/O devices in certain situations, and which making automaticcontrol system to achieve physical decentralized control. In the printing and dyeingindustry, a lot of I/O signals exist in the control field, when transferred it using theway of traditional I/O, it will cause a lot of problems, such as wiring difficulties, largewiring area, serious interference, and serious corrosion. Aimed at such problems, thispaper proposed the design of remote I/O, and achieved the purpose such as physicaldispersion, high reliability, and good economic benefits.In this paper, the design of remote I/O system is based on rotary screen printingcontrol system. Analyzed the field situation of printing and dyeing system and thedevelopment process of remote I/O, and then clear the design purpose of the remoteI/O.From a practical view, designed the overall framework of the remote I/O system,it is consisted of main module and vice module. Used CAN bus and485bus as thecommunication bus. Discussed the entire hardware design of the remote I/O system indetail, in the main module, which is included of power supply circuit, communicationcircuit, and the I/O output circuit, in the vice module which is included of powersupply circuit, communication circuit, and indicator circuit. Designed and discussedthe user-defined data frame format of the data field in CAN message, analyzed theModbus-ASCII protocol of the485bus and the whole design of the communicationprogram. Described the specific application framework of remote I/O system which isused in rotary screen printing control system, analyzed its contribution to the entiresystem. Designed a specific coding of the signal acquisition of the field I/O, andtested the feasibility of remote I/O system through specific application testing.The design of the remote I/O system greatly improved the stability and reliabilityof the rotary screen printing control system. |
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