Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 202)

ASCII Module
PLC-2 Family Processors
Appendix A
AĆ34
User program contains 20K words
Channel 1 contains four I/O chassis, with a total of three block transfer
modules including one ASCII module
Channel 2 contains two I/O chassis with no block transfer modules
Channel 3 contains two I/O chassis with one ACII module
Channel 4 is made inactive through processor LIST
You can compute the read or write block transfer times for the supervisory
processor in this example in four steps. Each of the following steps is
explained by an accompanying figure.
1. Diagram the I/O channels of your PC system (Figure B.3), showing
the number of:
block transfer modules in each I/O chassis
block transfer I/O channels
I/O chassis entries in the rack list for each block transfer I/O channel
active I/O channels per scanner
A block transfer I/O channel is a channel that contains one or more block
transfer modules located in any chassis connected to the channel.
An I/O chassis can appear more than once in a rack list of I/O chassis.
Count it and the block transfer module(s) that it contains as often as it is
listed.