User manual

105G Wireless Gateway User Manual
Elpro_man_105g_1.18.doc Page 128
- (0x01) Illegal function for the addressed slave
- (0x02) Illegal data address within the information field for the addressed slave
- (0x03) Illegal data value in the information field for the addressed slave
The 105G Modbus Plus supports up to 1024 words of output data and 1024 words of input data.
Converting this to 40000 registers, the possible output registers (Data to Network) range is
40001 – 41024 of which the first 32 words (i.e. 40001 – 40032) are global output data. However
all output registers, including the global output registers, may also be read from the module
using the point-to-point command Read Holding Registers (0x03). The possible input registers
(Data From Network) range is 41025 – 42048 of which the first 32 words (i.e. 41025 – 41056) is
global input data (i.e. data extracted from another network device’s global output data). Only
data not assigned to global input data (i.e. 41057 – 42048) may be written by the point-to-point
preset register commands.
4.14.4 Configuration
The “Node Address” will be the Modbus Plus network address of the 105G, (allowable values
are 1 – 64) and must be unique for the network segment. The “Source Address” will be the
Modbus Plus network address of another module on the network from which the 105G will
extract Global Data (i.e. Data From Network). Only 1 source address can be added to the
configuration (i.e. you can only extract data from one source device). “GDB I/P Count” (up to
32 words max) specifies the amount of Global Data to extract from the “Source Address” each
cycle. An offset into the source unit’s global data (“GDB I/P Offset”) may also be specified in
order to read a specific portion of the 32 word global data of the source address. However, since
only 32 words max of global data are produced, the sum of GDB I/P Offset and GDB I/P Count
must never exceed 32. After setting these parameters, the 105G I/O Registers must be linked to
Modbus Plus 40000 registers with appropriate “Fieldbus mappings”.
In the below example there is one “Fieldbus Write Mapping” (this will make available Data To
Network) and one “Fieldbus Read Mapping” (this will make available Data From Network).