Weidmuller WI-I/O-9-U2: Wireless Mesh I/O & Gateway User Manual V1.2.2 - Manual (Page 15)

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1.2 Module Structure
Figure 1 – Module Structure
The WI-I/O 9-U2 is made up of a number of basic sections, which all interface with a
central Input and output storage area (I/O Store).
The I/O Data Store provides storage for I/O data as well as providing services to other
processes in the system. The I/O Store provides eight different blocks of data - two
containing input and output bit data, two containing input and output word data, two
containing long-word type data and two containing floating-point data. The two files of
each type in turn support inputs and outputs on the local machine, and data storage for
the gateway function of the machine. These files are mapped into the address map as
described below. There are other registers within the database that can be used for
system management - these will be discussed later in this manual.
The Radio Interface allows the WI-I/O 9-U2 to communicate with other modules within
the system using a proprietary
radio protocol called “WIBMesh”. Messages from other
WI-I/O 9-U2 modules are received by the radio port and used to update the input values
in the I/O Data Store. The WIBMesh protocol is an extremely efficient protocol for radio
communications. Radio messages can be sent using exception reporting - that is, when
there is a change of an input signal - or by read/write messages. Each message will be
comprised of multiple I/O values termed as a
“block” of I/O). There are also update
messages, which are sent for integrity purposes.
Messages allow error checking, with the destination address sending a return
acknowledgment. Up to four attempts are made to transmit the message over each hop
of the radio path, if no acknowledgement is received. The WIBMesh protocol is
designed to provide reliable radio communications on an open license-free radio
channel.
The On-Board I/O in the form of - 8 discrete I/O, 2 single ended analog inputs, 2
differential analog inputs, and 2 current sourcing analog outputs. Each discrete I/O can
function as either a discrete input (voltage free contact input) or discrete output