Rockwell Automation 1791-I0VX BLOCK I/O - Manual (Page 12)

Introducing Block I/O
Chapter 1
1-6
Block I/O functions exactly like any Allen-Bradley remote I/O product.
Input and output data is scanned asynchronously and transferred back and
forth between the block and the controller input and output image table.
You connect the block I/O to your remote I/O link as you would any other
device. The block looks like a 1/2 I/O rack to the processor, and uses 4
words of input image table memory and 4 words of output image table
memory. The block is addressed directly on the remote I/O link.
Figure 1.6
Block I/O Connection in a PLC System
Blocks are daisy-chained to
a programmable controller,
or scanner.
Block I/O - each block
is 1/2 I/O rack.
Programmable Controller,
or Scanner
10915-I
In this chapter you learned what block I/O is, its features and
how it functions. Summary