Rockwell Automation 1785-L20C_L40C, D17856.5.14 ControlNet PLC-5 Programmable Controllers User Manual - Manual (Page 35)

Chapter 2
Planning to Use Your ControlNet
PLCĆ5 Processor
2-7
All scheduled data transfers must be mapped on a ControlNet network.
You specify where I/O data is to be read from or written to—i.e., mapped.
You do this and establish the relationship between processors, I/O adapters,
and data-table file addresses by creating and maintaining an I/O map table.
An I/O map-table entry is required for each scheduled data transfer. The
map table is stored in the configuration section of memory and is not
accessible by your application program.
Using the 6200 PLC-5 Programming Software, you can automatically
configure and map nodes attached to your ControlNet I/O. See Chapter 3
for information on ControlNet automatic configuration and I/O mapping.
Reserving Space for NonĆControlNet I/O
Non-ControlNet processor-resident local I/O and remote-I/O devices can
only use fixed I/O image locations based on rack number for discrete I/O
data transfer, while discrete I/O data transfer between ControlNet nodes
can be mapped to any unused location in the I/O image tables. Before
mapping your ControlNet I/O, therefore, you should configure any
processor-resident local I/O and any remote I/O racks on non-ControlNet
channels. This allows the 6200 PLC-5 Programming Software to reserve
input- and output-image space for all non-ControlNet processor-resident
local I/O and remote-I/O chassis.
ProcessorĆResident Local I/O
If you first configure processor-resident local I/O on your processor, the
6200 PLC-5 Programming Software reserves processor-resident local
chassis input- and output-image space starting at offset 0 in both files.
The following table shows the default number of input and output words
automatically reserved by the 6200 PLC-5 Programming Software for the
different sizes and addressing modes of processor-resident local I/O:
Addressing Mode
Number of Words Reserved
Addressing Mode
4 Slots 8 Slots 12 Slots 16 Slots
2 Slot 8 8 8 8
1 Slot 8 8 16 16
1/2 Slot 8 16 24 32
Important: ControlNet I/O cannot map into any part of a rack number
used by the processor-resident rack.
Understanding ControlNet
I/O Mapping