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@@ -54,9 +54,13 @@ Modbus RTU message must be transmitted continuously without inter-character
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hesitations (extract from Wikipedia, Modbus, http://en.wikipedia.org/wiki/Modbus
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(as of Mar. 13, 2011, 20:51 GMT).
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+The Modbus RTU framing calls a slave, a device/service which handle Modbus
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+requests, and a master, a client which send requests. The communication is
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+always initiated by the master.
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+
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Many Modbus devices can be connected together on the same physical link so you
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need to define which slave is concerned by the message with
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-linkmb:modbus_set_slave[3]. If you're running a slave (server) the slave number
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+linkmb:modbus_set_slave[3]. If you're running a slave, the slave number
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is used to filter messages.
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Create a Modbus RTU context::
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@@ -124,10 +128,11 @@ Flush a connection::
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linkmb:modbus_flush[3]
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-Data
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-~~~~
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+Client
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+~~~~~~
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The Modbus protocol defines different data types and functions to read and write
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-them from/to remote devices.
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+them from/to remote devices. The following functions are used by the clients to send
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+Modbus requests:
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Read data::
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linkmb:modbus_read_bits[3]
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@@ -141,6 +146,24 @@ Write data::
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linkmb:modbus_write_bits[3]
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linkmb:modbus_write_registers[3]
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+Raw requests::
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+ linkmb:modbus_send_raw_request[3]
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+ linkmb:modbus_receive_confirmation[3]
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+
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+
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+Server
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+~~~~~~
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+The server is waiting for request from clients and must answer when it is
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+concerned by the request. The libmodbus offers the following functions to
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+receive and reply:
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+
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+Receive::
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+ linkmb:modbus_receive[3]
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+ linkmb:modbus_receive_from[3]
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+
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+Reply::
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+ linkmb:modbus_reply[3]
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+
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ERROR HANDLING
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--------------
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Stéphane Raimbault