Product manual
B Protocols TAC Xenta Server – Gateway, Technical Manual
124 (184) Schneider Electric Buildings AB, June 2011
04-00124-06-en
Most Modbus device documents list their registers by number, but
some list them by the equivalent address that is 1 less than the reg-
ister number. Similarly, many documents do not clearly state what
type of register it is (coil, holding and so on), in which case the
function codes from the table above may be required to determine
what number range to enter.
J-Bus is a derivative sub-set of Modbus that only supports a single
register address space compared to the standard 4. And most J-Bus
slaves list their register numbers in hexadecimal form hence the X
address prefix is used to denote a J-Bus address.
• Register Table – If Full Address range is used, select the table
type Discrete Input, Coil, Input Register or Holding Register in
this column. If Fixed Address Blocks is used, all types have to be
set to Fixed Address Blocks.
• Register Data Type – Selects the format of the value within the
slave’s memory. Most register values are 16-bit signed or unsigned
integers, or 1 bit switch/coil status flags. But two registers can be
combined into one 32-bit integer or floating-point value. And in
some cases 2, 3 or 4 registers are combined into a single integer
30001–40000 4 Read one or more 16-bit input registers. (Input Regis-
ter)
40001–50000 3, 6, 10 Read and write one or more 16-bit holding registers.
(Holding Register)
X0001–XFFFF (hex) 3, 6, 10 Read and write one or more 16-bit J-Bus registers.
Table B.1: Fixed Address Blocks number ranges (Contd.)
Fixed Address Blocks
number ranges
Functions
codes
Description
Table B.2: Full Address number ranges
Full Address number
ranges
Functions
codes
Description
00001– 65536 1, 5 Read and write a single-bit coil state. (Coil)
00001– 65536 2 Read a single-bit input status. (Descrete Input)
00001– 65536 4 Read one or more 16-bit input registers. (Input Regis-
ter)
00001– 65536 3, 6, 10 Read and write one or more 16-bit holding registers.
(Holding Register)
X0001–XFFFF (hex) 3, 6, 10 Read and write one or more 16-bit J-Bus registers.