Manual

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. Y

ou 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 Pr

ogrammable Contr

oller 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.

Configuring Nondiscrete

I/O Data T

ransfers

ary