Starting Your Processor
Chapter 5
5-8
Figure 5.6
Illustration of 2Slot Addressing with 16Point Input and Output Modules
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16point input and output modules use
two words (one input, one output) of the
image table.
Output image table word corresponding
to the I/O group (all bits used)
Input image table word corresponding
to the I/O group (all bits used)
input
terminals
2slot
I/O group
output
terminals
Because these modules use a full word in the image table, the only type of
module you can use in a 2-slot I/O group with a 16-point module is one
that performs the opposite (complementary) function; an input module
complements an output module and vice-versa.
You can use an 8-point module with a 16-point module in a 2-slot group;
however, it too must perform the opposite function. Eight bits in the I/O
image table are unused.
Important: 32-point modules will not work in 2-slot addressing mode.
