Allen-Bradley PLC-5 User Manual page 48

4-4 Addressing I/O and Controller Memory
0 1
Input Input
Terminals
Termi
00
nals
01
02
03
04
05
06
07
Group 0
An 8-point I/O module occupies
1
8 bits in a word. See
4 5
Input
Terminals
00
01
02
03
04
05
06
07
Group 4 Group 5
An 8-point input module in group 4
occupies the first eight bits of input
word 4. The 8 point output module
occupies the first 8-output bits in
output word 5. See 3
Publication 1785-UM012D-EN-P - July 2005
18-and 16-point Example
2 3
Input
Terminals
00
10
01
11
02
12
03
13
04
14
05
15
06
16
07
17
Group 2
Two 8-point input modules occupy 8
bits of each group. See
Input
Terminals
Output 00
01
Terminals
02
03
00
04
01 05
06
02
07
03
10
11
04
12
05
13
06
14
15
07
16
17
Group 6
16-point I/O modules occupy 16 bits,
an entire word, in the image table.
See
4
1-slot addressing (1 I/O chassis slot = 1 I/O group = 1 input image
word and 1 output image word = 16 input bits and 16 output bits.)
Controller memory
Rack x
Word #
Input
Terminals
00
3
01
02
03
4
04
05
06
07
Word #
1
Group 3
2
2
3
4
6 7
Output
Terminals
00
01
02
03
04
05
06
07
10
11
12
13
14
15
16
17
Group 7
Output Image Table
0
1
2
3
4
5
6
7
17
Input Image Table
0
1
2
3
4
5
6
7
17
If you were to address the device attached to
this output circuit in your control program, the
address would be O:xx7/17.
00 bits
00 bits