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Chapter
5
Publication 1771ĆUM006B-EN-P - June 2002
Single Transfer Programming
Single transfer programming is one method for coordinating and
controlling bidirectional module/processor communication. This
method can only be used when the module is in a local I/O chassis.
Single transfer may be the recommended method even where block
transfer capability is available. Specifically, single transfer
programming is suggested whenever preset #1 words and #2 are not
used. When one or both preset words are used, block transfer
methods may be more efficient, depending on the application.
The material for single transfer programming is organized as
follows:
•
Section titled
Output Words - Single Transfer
describes the
configuration of output words when using single transfer
methods.
•
Section titled Single Transfer Description gives a general
description of how single transfer programming works and an
example for applications where no preset words are required.
•
Section titled Multiplexing shows how multiple words of output
data are multiplexed in single transfer.
•
Section titled Example Program - Single Transfer gives a
sample program for single transfer programming.
The output control and preset words have a unique configuration
when single transfer programming has been selected. Initially, the
program must set the bits in these words to the desired combination
for the application. Then, using single transfer techniques, the
program sends these output words to the module.
Output Control Word
Figure 5.1 shows the configuration of the output control word for
single transfer. By setting bits in this word, you set up the initial
mode of module operation and change it as required during
operation.
General
Output Words Ć Single
Transfer