與用戶儀表交互測量和控制訊號是用戶自動化策略的核心。橫河電機支持各種Fieldbus技術,包括傳統的4~20 mA、有線數字網絡和無線ISA100.11a標準。這些技術可根據用戶需求應用於設備、主機和解決方案層級。
The VJET Ethernet/RS-485 converter is a compact, plug-in type communication converter that uses the Modbus/TCP for connecting to host devices with Ethernet, and uses the Modbus/RTU for connecting to devices with RS-485.
Plug-in type, RS232C/RS485 dual directional converter with two ports of RS232C and RS485, and perform isolation of communication signal, level conversion and active control of driver.
The changes in social environment, such as globalization of enterprise activities, depletion of natural resources, and eco-oriented movement will affect the structure of mass production. Control systems must be prepared with flexibility and scalability in both size and function to adjust to the changes.
To configure a compact, low-power medium attachment unit for field buses, i.e., a fieldbus MAU, an IC comprising a power generator, transmitter/receiver and other functions is needed. While we at Yokogawa had already developed a fieldbus MAU IC, we have now developed another MAU IC that includes large-scale design changes made mainly to comply with the low-power signaling requirements of the fieldbus specifications.
Progress in digital signal processing and network technologies has enabled advanced functions which cannot be achieved by traditional field devices with 4-20 mA signal, to be implemented on field devices. Standardization of international fieldbus specifications, notably the FOUNDATION™ Fieldbus, has enabled users to build optimum field networks comprised of freely chosen field devices from various device vendors.
March 2007
Here's how Shell upgraded from a pneumatic instrumented plant to a fully digital control system.
2011
Decades of operation, modernization and expansion have left many chemical plants with a somewhat haphazard automation mix of different controls, process control systems, remote I/Os and field devices. The various components may use different communication protocols such as HART, PROFIBUS or FOUNDATION Fieldbus, and are often based on different device integration technologies.