Rockwell Automation 1771ACN/B_1771ACNR/B,D17716.5.123 U.MNL CONTROLNET ADAPTER - Manual (Page 30)

Addressing Modes for Your I/O 3–6
Publication 1771-6.5.123 – May 1996
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
(NO TAG). 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 Two Words of the Image Table
17 16 15 14 12 10 07 06 05 03 02 01 00 04 11 13
O utput im age table w ord corresponding
to the I/O group.
17 16 15 14 12 10 07 06 05 03 02 01 00 04 11 13
Input im age table w ord 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
Term inals O utput
Term inals
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.