Foundation Fieldbus H1


FOUNDATION Fieldbus H1 is one of the FOUNDATION fieldbus protocol versions. FOUNDATION H1 (31.25 kbit/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 significant improvement over the standard 4-20 mA communication method which requires a separate connection point for each communication device on the controller system.

From a business standpoint, FOUNDATION Fieldbus 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 a two wire communication is 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 fields devices as possible on controller field connection, limited only by signal strength.