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Foundation Fieldbus H1 is one of the Foundation Fieldbus protocol versions.FOUNDATION H1(31.25kbit/s) is a bi-directional communications protocol used for communications among field devices and to the control system. It utilizes either twisted pair, or fiber media to communicate between multiple nodes (devices) and the controller. The controller requires only one communication point to communicate with up to 32 nodes, this is a drastic improvement over the standard 4-20mA communication method which requires a separate communication point for each communication device on the controller system. From a business standpoint, FOUNDATION technology delivers savings in total installation costs. H1 Fieldbus reduces instrument wiring, which means less termination and fewer screwdriver turns. The technology reduces hardware requirements and lowers Capital Expenditures (CAPEX). FOUNDATION fieldbus primarily reduces Operating Expenses (OPEX) through improved plant efficiencies, better asset management, and reduced maintenance requirements.Specific benefits of FOUNDATION technology include: reduced wiring, multi-variables from a single multi-channel field instrument, simpler integration and easier maintenance. Using Half Duplex RS485 hardware connection the two wire communication is made possible. The Foundation Fieldbus H1 has support for Intrinsically Safe Wiring. Unlike other protocols, FOUNDATION H1 provides explicit synchronization of control and communication for precisely periodic (isochronous) communication and execution of control functions with minimized dead time and jitter. It synchronizes clocks in fieldbus devices for support of Function Block scheduling and alarm time-stamping at the point of detection. The original concept was to connect as many as can be in forming a node,but limited by signal strength. ==Foundation HSE== FOUNDATION HSE is a control network technology specifically designed for process automation to connect higher-level devices such as controllers and remote-I/O, high-density data generators etc., and for horizontal integration of subsystems. FOUNDATION HSE is based on unmodified IEEE 802.3 Ethernet and, therefore, is compatible with standard Ethernet equipment. Unlike mere "ring topology,” FOUNDATION HSE provides complete "DCS style" redundancy with redundant network switches, redundant devices, and redundant communication ports ensuring unsurpassed availability. FOUNDATION HSE is also based on standard IP, enabling it to coexist with other devices and ensuring compatibility with standard tools. At the highest level, FOUNDATION HSE includes a standard application layer that provides interoperability between devices beyond the mere coexistence provided by Ethernet and TCP/IP. FOUNDATION HSE communication is schedule-driven to minimize dead-time and jitter with support for peer-to-peer communication directly between devices. Again, a rigorous interoperability testing program ensures quality connectivity. The hub-and-spoke tree topology of Ethernet makes it very easy to add and remove devices without upsetting the operating network. Because FOUNDATION HSE is based on unmodified Ethernet, standard Ethernet tools can be used for installation qualification, testing, and troubleshooting. These tools speed up the resolution of communication problems. FOUNDATION HSE is supported by better troubleshooting tools not available for RS485 and coax. Since FOUNDATION HSE is based on UDP and TCP, standard network management tools employing SNMP, RMON, etc., can be used. Similarly, familiar IP addressing is used including support for DHCP. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Foundation Fieldbus H1」の詳細全文を読む スポンサード リンク
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