In order to ensure the integrity of communication,most DCS manufacturers can provide redundant data bus.In order to ensure the security of the system,complex communication protocols and error detection techniques are used.The so-called communication protocol is a set of rules to ensure that the transmitted data is received and understood as the transmitted data.At present,two types of communication means are generally used in DCS systems,namely synchronous and asynchronous.Synchronous communication relies on a clock signal to adjust the transmission and reception of data,and asynchronous networks use a reporting system without a clock.
为保证通信的完整,大部分DCS厂家都能提供冗余数据总线。为了保证系统的安全性,使用了复杂的通信规约和检错技术。所谓通信规约就是一组规则,用以保证所传输的数据被接收,并且被理解得和发送的数据一样。目前在DCS系统中一般使用两类通信手段,即同步的和异步的,同步通信依靠一个时钟信号来调节数据的传输和接收,异步网络采用没有时钟的报告系统。
MITSUBISHI A1S38B MELSEC 7 SLOT RACK/CHASSIS ,BASE UNIT
LOAD CONTROLS INCORPORATED PFR-1700 GOOD TAKEOUT
COLUMBUS ELECTRIC BKTD-110 VENTILATION THERMOSTAT ,
CINCINNATI MILARCON 3-531-4380A CONTROL BOARD GOOD TAKE
DATA INSTRUMENTS SA 0-200 PSIS (9305905)
DATA INSTRUMENTS SA 0-500 PSIS (9305907)
MITSUBISHI AJ65VBTCUS-16D1 (CC-LINK INPUT UNIT)