Welcome to HotRIO Hardware documentation!
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The HotRIO instrumentation system, originally developed and marketed by Fusion For Energy (F4E), is a distributed data acquisition and processing platform designed to provide remote I/O capabilities for the control systems of large-scale fusion experiments.

HotRIO offers a scalable and flexible ecosystem of remote I/O hardware that interfaces with standard off-the-shelf network equipment, such as fiber optic cables. The system leverages a custom communication protocol, the **HotRIO protocol**, to enable high-speed, low-latency, and deterministic communication between nodes. This protocol ensures reliable data exchange and control command transmission across the system.

HotRIO Hardware catalogue can be obtained `here <./datasheets/HotRIOCatalogue.pdf>`_

For details on the hardware nomenclature system, please refer to the `nomenclature documentation page <../Nomenclature.html>`_.

.. For details on the HotRIO protocol, refer to the `HotRIO Protocol Specification <../../../../../HotRIO-Software/Documentation/build/html/design/protocol.html>`_.

Hardware Components of a HotRIO node
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A HotRIO node is usually made up of a set of components, which can be broadly categorized into three groups:

- **HotRIO Controller Boards**: These boards form the backbone of the communication chain, enabling data exchange over fiber optics using the HotRIO protocol. Equipped with an FPGA, they handle protocol communication and interface with external signals. However, they lack direct hardware for physical signal interfacing.

- **HotRIO Expansion Boards**: These boards provide the interfaces required to connect HotRIO controller boards to the physical world. They support digital I/O, analog I/O, and communication interfaces such as Ethernet or RS-232/RS-485. Expansion boards are connected to HotRIO controller boards via aggregator boards (if necessary) and are directly controlled by the node's FPGA. These boards are designed to be modular and can be customized based on the application requirements.

- **HotRIO Aggregator Boards**: These boards facilitate connections between HotRIO controller boards and one or more expansion boards. They may also provide auxiliary functions such as power distribution or signal conditioning for communication pathways.

The combination of these components forms a HotRIO node, enabling the system to interface with external devices, process data, and communicate with other nodes within the HotRIO loop. The flexibility of the HotRIO system allows users to customize the node's capabilities by selecting and configuring the appropriate components based on their application requirements.


.. toctree::
   :maxdepth: 1
   :caption: Contents:

   Nomenclature
   boards/index
   licence