Product manual

TAC Xenta Server – Gateway, Technical Manual B Protocols
Schneider Electric Buildings AB, June 2011 133 (184)
04-00124-06-en
• Register Number– Allows the base number of each required
Modbus register set to be selected. The entered number should
contain 5 characters in one of the following forms:
• Register Type – Selects the format of the value within the slave’s
memory. Most register values are 16-bit signed or unsigned inte-
gers, or 1 bit switch/coil status flags. The Modbus Slave driver
does not support 32-bit integer or floating point registers.
• Bit Mask Start and Stop – Allows several signals to be split off
from the applicable N-bit subsets of a single register. The mask
should be left blank to utilize all 16 bits of the register, or the
applicable start and stop bits entered to match the required sub-set
of bits within it. Several different bit masks can be applied to the
same register to monitor different parts of it.
• I/O Signal Direction – Most Modbus Slave device signals are
used to monitor a register’s value, in which case the I/O column
parameter should be set to Read-only (R). This setting allows the
master to write to the pseudo registers within the Xenta 913, effec-
tively allowing these to be read from the master by the LON or
I/Net control system.
Table B.3: Register numbers.
Number
Range
Format Functions Description
00001–10000 Decimal 1, 5 Read and write a single-bit coil state.
10001–20000 Decimal 2 Read a single-bit input status.
30001–40000 Decimal 4 Read one or more 16-bit input registers.
40001–50000 Decimal 3, 6, 10 Read and write one or more 16-bit holding registers.
X0001–XFFFF Hex 3, 6, 10 Read and write one or more 16-bit J-Bus registers.
Notes
• J-Bus is a derivative sub-set of Modbus that only supports a sin-
gle register address space compared to the standard 4. And J-Bus
register addresses are normally entered using hexadecimal num-
bers, hence the X address prefix is used denote a J-Bus address.
• It may be necessary to enter register numbers to match the expec-
tation of the master. But in most cases any register numbering
scheme may be used and the master configured to suit.