1MODBUS_REPORT_SLAVE_(3)        Libmodbus Manual        MODBUS_REPORT_SLAVE_(3)
2
3
4

NAME

6       modbus_report_slave_id - returns a description of the controller
7

SYNOPSIS

9       int modbus_report_slave_id(modbus_t *ctx, uint8_t *dest);
10

DESCRIPTION

12       The modbus_report_slave_id() function shall send a request to the
13       controller to obtain a description of the controller.
14
15       The response stored in dest contains:
16
17       ·   the byte count of the response
18
19       ·   the slave ID, this unique ID is in reality not unique at all so
20           it’s not possible to depend on it to know how the information are
21           packed in the response.
22
23       ·   the run indicator status (0x00 = OFF, 0xFF = ON)
24
25       ·   additional data specific to each controller. For example, libmodbus
26           returns the version of the library as a string.
27

RETURN VALUE

29       The modbus_report_slave_id() function shall return the number of read
30       data if successful. Otherwise it shall return -1 and set errno.
31

EXAMPLE

33           uint8_t *tab_bytes;
34
35           ...
36
37           rc = modbus_report_slave_id(ctx, tab_bytes);
38           if (rc > 1) {
39               printf("Run Status Indicator: %s\n", tab_bytes[1] ? "ON" : "OFF");
40           }
41

AUTHORS

43       The libmodbus documentation was written by Stéphane Raimbault
44       <stephane.raimbault@gmail.com[1]>
45

NOTES

47        1. stephane.raimbault@gmail.com
48           mailto:stephane.raimbault@gmail.com
49
50
51
52libmodbus 3.0.6                   04/02/2014           MODBUS_REPORT_SLAVE_(3)
Impressum