Rockwell Automation 1747-SN Remote I/O Scanner User Manual
Page 47
Publication 1747-UM013B-EN-P - January 2005
Scanner Configuration and Programming 4-3
The 1747-SN Scanner’s I/O image structure is described below:
• The I/O image file consists of four logical racks (numbered
0,1,2, and 3) of input image and four logical racks of output
image.
• Each logical rack consists of eight logical groups
(numbered 0, 1, 2, 3, 4, 5, 6, and 7).
• Each logical group consists of two words (an input word and an
output word).
• Each word consists of two bytes (a high and a low byte). Low
byte is bits 0 to 7 and high byte is bits 8 to 15.
• Each byte consists of 8 bits with each bit having the ability to
control one discrete I/O point.
Logical Rack 3 Group 6
Logical Rack 3 Group 7
Logical Rack 1 Group 2
Logical Rack 1 Group 3
Logical Rack 1 Group 0
Logical Rack 1 Group 1
Logical Rack 1 Group 6
Logical Rack 1 Group 4
Logical Rack 1 Group 5
Logical Rack 0 Group 6
Logical Rack 0 Group 7
Logical Rack 0 Group 4
Logical Rack 0 Group 5
Logical Rack 0 Group 2
Logical Rack 0 Group 3
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Bit Number (decimal)
SLC Input
File Address
I:e.0
I:e.1
I:e.2
I:e.3
I:e.4
I:e.5
I:e.6
I:e.7
I:e.8
I:e.9
I:e.10
I:e.11
I:e.12
I:e.13
I:e.14
I:e.30
I:e.31
Word 0
Word 1
Word 2
Word 3
Word 4
Word 7
Word 8
Word 9
Word 10
Word 11
Word 12
Word 13
Word 14
Word 5
Word 6
Word 30
Word 31
Logical Rack 0 Group 0
Logical Rack 0 Group 1
Logical Rack 3 Group 1
Logical Rack 3 Group 2
Logical Rack 2 Group 7
Logical Rack 3 Group 0
Logical Rack 3 Group 5
Logical Rack 3 Group 3
Logical Rack 3 Group 4
Logical Rack 2 Group 5
Logical Rack 2 Group 6
Logical Rack 2 Group 3
Logical Rack 2 Group 4
Logical Rack 2 Group 1
Logical Rack 2 Group 2
I:e.15
I:e.16
I:e.17
I:e.18
I:e.19
I:e.20
I:e.21
I:e.22
I:e.23
I:e.24
I:e.25
I:e.26
I:e.27
I:e.28
I:e.29
Word 15
Word 16
Word 17
Word 18
Word 19
Word 22
Word 23
Word 2 4
Word 25
Word 26
Word 27
Word 28
Word 29
Word 20
Word 21
Logical Rack 1 Group 7
Logical Rack 2 Group 0
Logical
Rack 0
Logical
Rack 1
Logical
Rack 2
Logical
Rack 3
0
8
1
8
2
8
3
8
4
8
5
8
6
8
7
8
10
8
11
8
12
8
13
8
14
8
15
8
16
8
17
8
Bit Number (octal)
e = slot number of the SLC chassis containing the scanner