2020-06-21 07:09:15 +08:00
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.. _modbus:
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2021-12-14 06:21:01 +08:00
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Modbus
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2020-06-21 07:09:15 +08:00
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######
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2021-04-15 20:17:34 +08:00
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Modbus is an industrial messaging protocol. The protocol is specified
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for different types of networks or buses. Zephyr OS implementation
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supports communication over serial line and may be used
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with different physical interfaces, like RS485 or RS232.
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TCP support is not implemented directly, but there are helper functions
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to realize TCP support according to the application's needs.
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2020-06-21 07:09:15 +08:00
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2021-04-15 20:17:34 +08:00
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Modbus communication is based on client/server model.
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Only one client may be present on the bus. Client can communicate with several
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server devices. Server devices themselves are passive and must not send
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requests or unsolicited responses.
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Services requested by the client are specified by function codes (FCxx),
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and can be found in the specification or documentation of the API below.
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Zephyr RTOS implementation supports both client and server roles.
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More information about Modbus and Modbus RTU can be found on the website
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`MODBUS Protocol Specifications`_.
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Samples
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*******
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2023-09-06 16:25:28 +08:00
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* :zephyr:code-sample:`modbus-rtu-server` and :zephyr:code-sample:`modbus-rtu-client` samples give
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the possibility to try out RTU server and RTU client implementation with an evaluation board.
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* :zephyr:code-sample:`modbus-tcp-server` sample is a simple Modbus TCP server.
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* :zephyr:code-sample:`modbus-gateway` sample shows how to build a TCP to serial line
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gateway with Zephyr OS.
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2021-04-15 20:17:34 +08:00
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API Reference
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*************
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.. doxygengroup:: modbus
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.. _`MODBUS Protocol Specifications`: https://www.modbus.org/specs.php
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