A basic goal of FOUNDATION fieldbus technology involves striving to create decentralized intelligence in field devices for process automation. When doing so, the field device is viewed as a conventional controller. Due to strong technological performance limitations in field devices, there is certainly much more development work needed by field device manufacturers.

Transfer medium for the field device
The physical layer is based on the IEC 61158 standard, just like PROFIBUS PA. The following properties result from this: - Supply voltage and communication is handled over two wires, the "EEx" and "non-Ex" designs are available. - Polarity protection for the device is possible/available. - The transfer rate is always 31.25 kBit/s - Up to 32 stations can be connected per segment, with FISCO/ EEx-ia IIC applications accepting up to 10 stations. - The line length can be up to 1900 m or 1000 m for EEx applications.

Unique field device addressing
Each FF device has a uniquely specified address. It is derived from the combination of manufacturer number (xxxxxx), device number/type (yyyy), and serial number (zzzzzzz), i.e. an FF device address is in the following form:  xxxxxxxyyyy-zzzzzzz. After the device has been detected on the fieldbus segment, the device configuration can be started through non-cyclic communication.

Link Active Scheduler (LAS)
Administrator tasks on the bus segment are carried out by the LAS (Link Active Scheduler). - Recognizing and publishing newly detected field devices on the bus. - Recognizing and publishing devices that are no longer present on the bus or that no longer communicate. - Creating the "live list". The "live list" is updated regularly by the LAS. - Querying process variables on the field devices according to the scheduler. - Passing off the token to the field devices between the respective data transfer.

Link Master (LM)
Link Master refers to the class of devices that have an Link Active Scheduler (LAS) function. Only one device with the Link Master function can be active as an LAS on the fieldbus. Redundancy is also possible using the LAS function. Depending on the manufacturer, a fieldbus device includes a FOUNDATION fieldbus device with n function blocks (e.g. 3 AI, 1 AO, 1 DO, 2 PID) and n transducer blocks (e.g. 1 flow, 1 display, 1 counter, 1 diagnostics). DD / CFF The manufacturer provides the device description using the device description language (device description as *.FFO files, *.SYM files). Capability files (in common file format as *.CFF files) are absolutely mandatory for offline engineering to take place.

Operation tips for Modbus/ TCP connections
The starting point is the Modbus/TCP port on the gateway. The connection to the controller is established physically via ETHERNET using the Modbus/TCP protocol. The gateway (similar to the PROFIBUS gateway) establishes the connection between ETHERNET with the Modbus/TCP protocol and the 4 H1 segments. The configuration of the H1 segments takes place using a separate H1 configuration tool. H1 segment process data can be read and written via the Modbus/TCP protocol. The H1 configuration tool also manages FF device configurations and the import of device descriptions. Through the additional use of a linking device (HSE/H1), the complete configuration of the H1 segments can be carried out from a centralized FF engineering station. An HSE configurator is used as a tool for configuration on the Engineering station.