Rockwell Automation 1747-DCM,D17476.8 Direct Communication Module - Manual (Page 29)

Chapter 3
Addressing
3–5
An image map is a diagram showing how the scanner image is mapped into
the image of multiple adapters. The following table and illustration show
how an example PLC output image is mapped into the image of multiple
SLC processors through the DCM.
PLC Scanner Output Image To: DCM SLC Input Image
O:011/10 Starting Group 0
(Rack 01, Group 1, Bit 10 octal)
→ 1
I:1.1/8
(Slot 1, Word 1, Bit 8 decimal)
O:021/3 Starting Group 0
(Rack 02, Group 1, Bit 3 octal)
→ 2
I:1.1/3
(Slot 1, Word 1, Bit 3 decimal)
O:025/13 Starting Group 2
(Rack 02, Group 5, Bit 13 octal)
→ 3
I:2.3/11
(Slot 2, Word 3, Bit 11 decimal)
Each row in the table represents the address of a data bit being transferred
from the PLC scanner output image to the SLC input image via three
different DCMs. The figure on the next page illustrates this data transfer.
Appendix B contains a worksheet designed to help you work out your DCM
system addressing. Use it if necessary to record I/O addresses.
Image Mapping