User manual

WI-MOD-9-E Wireless Ethernet User Manual
WI-MOD-9-E Manual V1.9 Page 50
The WI-MOD-9-E also provides ModBus TCP Client and ModBus TCP Server functionality for
I/O transfer. 5000 x 16bit general purpose registers are provided for ModBus (including the
onboard Digital Input/Output) and are shared for both Client and Server. ModBus TCP Client
(Master) and ModBus TCP Server (Slave) are both supported simultaneously, and when
combined with the built in ModBus TCP to RTU Gateway the WI-MOD-9-E can transfer I/O
to/from almost any combination of ModBus TCP or RTU devices.
The layout of the I/O registers is summarized in the table below. Each register is internally saved
as a 16 bit value. A ModBus transaction may access the entire 16 bit value of any register, or
alternatively the most significant bit of a register may be accessed as a discrete value. The main
use for the general purpose I/O registers is for intermediate storage, i.e. when transferring I/O
from one ModBus Slave device to another. Also provided is the status of the onboard digital I/O.
The 16 bit status register contain the value FFFF(hex) for ON and 0000(hex) for OFF. Inverted
status registers are also provided where the registers contain 0000(hex) for ON and FFFF(hex)
for OFF.
Registers Purpose
1 – 4299 General purpose I/O registers (read/write)
4300 On-board Digital Input value (read only)
4301 Reserved
4320 On-board Digital Output value (read/write)
4370 On-board Digital Input inverted value (read only)
4371-4999 Reserved for future use
ModBus TCP Client (Master) enables the WI-MOD-9-E to connect to one or more ModBus TCP
Servers (Slaves). All ModBus Master messages are directed either to/from the onboard I/O
registers depending on configuration (described below). The ModBus TCP Client may also poll
ModBus RTU (i.e. serial) devices connected to either the local serial port or a remote WI-MOD-
9-E serial port by enabling the ModBus TCP to RTU gateway at the corresponding serial port
(see section “3.13.3 ModBus TCP to RTU Gateway”). ModBus TCP Client functionality allows
connections to a maximum of 25 different ModBus TCP Servers.
ModBus TCP Server (Client) enables the WI-MOD-9-E to accept connections from one or more
ModBus TCP Clients (Masters). All ModBus transactions routed to the onboard ModBus TCP
Server are directed either to/from the onboard general purpose I/O registers. The ModBus TCP
Server is shared with the ModBus TCP to RTU Gateway, so that the ModBus “Device ID” is
used to determine if a ModBus transaction is to be routed to the onboard ModBus TCP Server or
to a ModBus RTU device connected to the serial port. Care should therefore be taken that all
serially connected ModBus devices use a different ModBus Device ID (i.e. ModBus Slave
Address) to the onboard ModBus TCP Server. Up to 32 separate connections to the ModBus
TCP Server are supported. ModBus RTU (serial) Master functionality is achieved by combining
the ModBus TCP Client (Master) and ModBus TCP to RTU Gateway. Simply specify a ModBus
TCP Client (Master) connection to a ModBus TCP Server where the server is the address of any