User's Manual

Page 10 E2 Wireless I/O
1.2 Module Structure
The E2 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 register values within the database that can be used
for system management - these will be discussed later in this manual.
The Radio Interface allows the E2 to communicate with other modules within the
system using a proprietary radio protocol called “WIB-Net”. Messages from other E2
modules are received by the radio port and used to update the input values in the I/O
Data Store. The WIB-Net 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 include error checking, with
the destination address sending a return acknowledgment. Up to five attempts are
made to transmit the message if an acknowledgment is not received. The WIB-Net
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 is
either a discrete input (voltage free contact input) or discrete output (transistor output).
Each I/O point is linked to separate I/O registers within the I/O Data Store.