Understanding the terms used in this chapter – Rockwell Automation 1785-LTx,D17856.2.1 Classic PLC-5 Programmable Controllers Users Manual User Manual
Page 44

Assigning Addressing Modes,
Racks, and Groups
Chapter 4
4-2
The following guidelines are for placing block-transfer modules.
Place as many modules as possible for which you need fast
block-transfer times in your processor-resident local I/O chassis .
Place modules that need fast block-transfer times (but space is not
available in processor-resident local I/O chassis) in an extended-local
I/O chassis.
Place modules in which timing is not as critical as in other
block-transfer modules in remote I/O chassis.
ac output modules should always be the furthest I/O modules from any
block-transfer modules in the same chassis.
Become familiar with the following terms and their definitions:
An I/O group is an addressing unit that corresponds to an input
image-table word (16 bits) and an output image-table word (16 bits). An
I/O group can contain up to 16 inputs and 16 outputs; and it can occupy 2-,
1-, or 1/2-module slots for addressing purposes.
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13073
(I/O Group #0)
(I/O Group #0)
2ĆSlot I/O Module Group
1ĆSlot I/O Module Group
Input
Terminals
Output
Terminals
Output or
Input
Terminals
Understanding the Terms
Used in this Chapter