Peter M. Groen / libmodbus

Commit c7c7c768a6b60259b9e38df39a8da909b53a8791

Authored by Stéphane Raimbault
1 parent 0e2f470a

Improve new_rtu and set_slave documentation (related to #276)

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Showing 2 changed files with 38 additions and 1 deletions
doc/modbus_new_rtu.txt
  View file @c7c7c76
... ... @@ -15,7 +15,7 @@ SYNOPSIS
15 15  
16 16 DESCRIPTION
17 17 -----------
18   -The *modbus_new_rtu()* function shall allocate and initialize a modbus_t
  18 +The *modbus_new_rtu()* function shall allocate and initialize a _modbus_t_
19 19 structure to communicate in RTU mode on a serial line.
20 20  
21 21 The _device_ argument specifies the name of the serial port handled by the OS,
... ... @@ -37,6 +37,9 @@ values are 5, 6, 7 and 8.
37 37 The _stop_bits_ argument specifies the bits of stop, the allowed values are 1
38 38 and 2.
39 39  
  40 +Once the _modbus_t_ structure is initialized, you must set the slave of your
  41 +device with linkmb:modbus_set_slave[3] and connect to the serial bus with
  42 +linkmb:modbus_connect[3].
40 43  
41 44 RETURN VALUE
42 45 ------------
... ... @@ -62,6 +65,14 @@ if (ctx == NULL) {
62 65 fprintf(stderr, "Unable to create the libmodbus context\n");
63 66 return -1;
64 67 }
  68 +
  69 +modbus_set_slave(ctx, YOUR_DEVICE_ID);
  70 +
  71 +if (modbus_connect(ctx) == -1) {
  72 + fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
  73 + modbus_free(ctx);
  74 + return -1;
  75 +}
65 76 -------------------
66 77  
67 78 SEE ALSO
... ...
doc/modbus_set_slave.txt
  View file @c7c7c76
... ... @@ -45,6 +45,32 @@ ERRORS
45 45 The slave number is invalid.
46 46  
47 47  
  48 +EXAMPLE
  49 +-------
  50 +[source,c]
  51 +-------------------
  52 +modbus_t *ctx;
  53 +
  54 +ctx = modbus_new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1);
  55 +if (ctx == NULL) {
  56 + fprintf(stderr, "Unable to create the libmodbus context\n");
  57 + return -1;
  58 +}
  59 +
  60 +rc = modbus_set_slave(ctx, YOUR_DEVICE_ID);
  61 +if (rc == -1) {
  62 + fprintf(stderr, "Invalid slave ID\n");
  63 + modbus_free(ctx);
  64 + return -1;
  65 +}
  66 +
  67 +if (modbus_connect(ctx) == -1) {
  68 + fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
  69 + modbus_free(ctx);
  70 + return -1;
  71 +}
  72 +-------------------
  73 +
48 74 AUTHORS
49 75 -------
50 76 The libmodbus documentation was written by Stéphane Raimbault
... ...