Commit 5f77c11403e585fb09b30c13264a82aa229bded0
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Updated libmodbus.txt documentation
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doc/libmodbus.txt
| ... | ... | @@ -54,9 +54,13 @@ Modbus RTU message must be transmitted continuously without inter-character |
| 54 | 54 | hesitations (extract from Wikipedia, Modbus, http://en.wikipedia.org/wiki/Modbus |
| 55 | 55 | (as of Mar. 13, 2011, 20:51 GMT). |
| 56 | 56 | |
| 57 | +The Modbus RTU framing calls a slave, a device/service which handle Modbus | |
| 58 | +requests, and a master, a client which send requests. The communication is | |
| 59 | +always initiated by the master. | |
| 60 | + | |
| 57 | 61 | Many Modbus devices can be connected together on the same physical link so you |
| 58 | 62 | need to define which slave is concerned by the message with |
| 59 | -linkmb:modbus_set_slave[3]. If you're running a slave (server) the slave number | |
| 63 | +linkmb:modbus_set_slave[3]. If you're running a slave, the slave number | |
| 60 | 64 | is used to filter messages. |
| 61 | 65 | |
| 62 | 66 | Create a Modbus RTU context:: |
| ... | ... | @@ -124,10 +128,11 @@ Flush a connection:: |
| 124 | 128 | linkmb:modbus_flush[3] |
| 125 | 129 | |
| 126 | 130 | |
| 127 | -Data | |
| 128 | -~~~~ | |
| 131 | +Client | |
| 132 | +~~~~~~ | |
| 129 | 133 | The Modbus protocol defines different data types and functions to read and write |
| 130 | -them from/to remote devices. | |
| 134 | +them from/to remote devices. The following functions are used by the clients to send | |
| 135 | +Modbus requests: | |
| 131 | 136 | |
| 132 | 137 | Read data:: |
| 133 | 138 | linkmb:modbus_read_bits[3] |
| ... | ... | @@ -141,6 +146,24 @@ Write data:: |
| 141 | 146 | linkmb:modbus_write_bits[3] |
| 142 | 147 | linkmb:modbus_write_registers[3] |
| 143 | 148 | |
| 149 | +Raw requests:: | |
| 150 | + linkmb:modbus_send_raw_request[3] | |
| 151 | + linkmb:modbus_receive_confirmation[3] | |
| 152 | + | |
| 153 | + | |
| 154 | +Server | |
| 155 | +~~~~~~ | |
| 156 | +The server is waiting for request from clients and must answer when it is | |
| 157 | +concerned by the request. The libmodbus offers the following functions to | |
| 158 | +receive and reply: | |
| 159 | + | |
| 160 | +Receive:: | |
| 161 | + linkmb:modbus_receive[3] | |
| 162 | + linkmb:modbus_receive_from[3] | |
| 163 | + | |
| 164 | +Reply:: | |
| 165 | + linkmb:modbus_reply[3] | |
| 166 | + | |
| 144 | 167 | |
| 145 | 168 | ERROR HANDLING |
| 146 | 169 | -------------- | ... | ... |