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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
Link Status (read only)
4320
On-board Digital Output value (read/write)
4370
On-board Digital Input inverted value (read only)
4371
Link Status inverted (read only)
4372-4999 Reserved for future use
ModBus TCP Client (Master) enables the WI-MOD-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-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 (Slave) enables the WI-MOD-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 WI-MOD-E with
ModBus TCP to RTU Gateway enabled. Care should be taken to ensure that the Device ID (i.e.
ModBus Address) of the serial device is different to the Device ID of the onboard ModBus TCP
Server of the WI-MOD-E that the serial device is connected to.
The WI-MOD-E provides a configurable option to automatically reset the value of the onboard I/O
registers to zero in the event of a communications failure. If a valid ModBus transaction directed
to/from a given register has not been completed for longer than a configurable timeout, then the
value of that register will be reset to zero.
