Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 97)

Advanced Instruction Set
Chapter 6
6Ć40
Done and Enable Bits
The read and write bits are the enable bits for block transfer modules. Either
one (or both for a bidirectional transfer) is set in the program scan when the
rung containing the block transfer instruction is true.
The done bit is set in the I/O scan that the words are transferred, provided that
the transfer was initiated and successfully completed. The done bit remains set
for only one additional program scan.
Block transfer will be requested in each program scan that the read and/or write
bits remain set. The read and/or write bits are turned off when the rung
containing the instruction goes false.
Block Transfer Read
Symbol: BLOCK
X-FER 1
Purpose: Reading information from a 1771 I/O module to the processor’s input
image table in one I/O scan.
Syntax: Programmed as an output instruction. This instruction requires two
words of your program.
Block Programming
Instructions