User Manual

3–6 Addressing Modes for Your I/O
Publication 1771-6.5.124 – August 1997
Using High-density (16 point) I/O Modules
16-point I/O modules provide 16 input terminals or 16 output
terminals. 16-point I/O modules use a full word in the input or
output image table when they are addressed as a 2-slot I/O group
(Figure 3.5). Two 16-point modules (one input and one output) can
be used in a 2-slot I/O group.
Figure 3.5
16-point Input and Output Modules Using T wo W ords of the Image T able
17
16 15 14 12
10
07
06
05 03
02 01 00
04
11
13
Output image table word corresponding
to the I/O group.
17 16 15 14 12
10
07
06
05 03
02 01
00
04
11
13
Input image table word corresponding
to the I/O group.
00
01
02
03
04
05
06
07
10
11
12
13
14
15
16
17
00
01
02
03
04
05
06
07
10
11
12
13
14
15
16
17
Input
Terminals
Output
Terminals
15559
2-slot I/O Group
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; it must perform the opposite function. However, eight bits in
the I/O image table are unused.