Rockwell Automation 1771ACN/B_1771ACNR/B,D17716.5.123 U.MNL CONTROLNET ADAPTER - Manual (Page 42)

Planning to Use Your ControlNet Adapter Module 4–6
Publication 1771-6.5.123 – May 1996
The following are important factors to consider when planning and
configuring nondiscrete I/O modules:
•
You can communicate with nondiscrete I/O modules anywhere in
the rack, including slots that are not mapped into the discrete I/O
image files. Note that nondiscrete I/O modules can be placed so
no I/O image space is used.
For example, in an 8-slot chassis with 1-slot addressing, you can place
discrete modules in the first 4 slots and only map 4 words of I/O image
table. You could then place nondiscrete modules in the last 4 slots
without using more I/O image space.
•
Slots in the adapter are physically referenced starting at 0 and
continuing by 1 up to a maximum of 15 (depending on the size of
your chassis) regardless of the addressing mode (2, 1, or 1/2) used
within the chassis.
•
The explicit ControlNet I/O transfer instruction (CIO) can also be
included in your ladder logic program to communicate with
nondiscrete I/O modules.
•
One or more connections are required per module, depending on
the type of module. A separate connection is used for a read or
write.
•
Modules accommodated by the processor’s nondiscrete I/O data
transfer mechanism are typically those that require a one-time
configuration and are continuously read from or written to.
Refer to the ControlNet PLC–5 Programmable Controller Use
Manual, publication 1784-6.5.14, chapter 2 for more information on
supported nondiscrete I/O modules.
In this chapter, you learned about adapter operation, discrete I/O data
transfer, configuring discrete I/O data transfer, nondiscrete I/O data
transfer, and configuring nondiscrete I/O data transfer. In addition,
you learned some important factors about nondiscrete I/O data
transfers.
Appendix B is an example of some of the concepts learned in this
chapter.
More
Configuring Nondiscrete
I/O Data Transfers
Chapter Summary