
1–3
Overview of FLEX I/O and your Analog Modules
Publication 17946.5.2 - May 1996
Figure 1.1
An Example of Communication Between an Adapter and an
Analog Input Module
ADAPTER
ACTIVE
FAULT
LOCAL
FAULT
24VDC
POWER SUPPLY
RIO ADAPTER
1794ASB
AllenBradley
2
AllenBradley
INPUT 0
INPUT 2
INPUT 4
INPUT 6
INPUT 1
INPUT 3
INPUT 5
INPUT 7
I V I V I V I V I V I V I
V I V
ANALOG INPUT
1794-IE8
1
The adapter transfers your configuration data
to the module using a BTW.
Flexbus
External devices transmit
analog signals to the module.
2
The module converts analog signals
into binary format and stores these
values until the adapter requests their
transfer.
3
Your ladder program instructs the
adapter to perform a BTR of the values
and stores them in a data table.
4
The adapter and module determine
that the transfer was made without error
and input values are within specified
range.
5
Your ladder program can use and/or move the data (if valid)
before it is written over by the transfer of new data in a
subsequent transfer.
6
Your ladder program performs BTWs to the module when you power
it up, and any time you wish to reconfigure the module.
7