Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 116)

Publication 1747-UM010B-EN-P - September 2003
7-4 RIO Block Transfer
4. Using the M1 file and a COP instruction in the control program
the scanner transfers the BTR data to the SLC processor via the
chassis backplane. The M1 file also contains BTR status
information. (Refer to the Block Transfer Buffer Layout section
for details on status information.)
5. The SLC control program processes the BTR information.
RIO Block Transfer Theory of Operation-Block Transfer Write (BTW)
The steps below detail a successful Block Transfer Write (BTW):
1. The user’s control program executes a MOV or COP instruction
to the MO file to initiate a BTW. The SLC processor sends BTW
data (via the chassis backplane) to the scanner’s MO block
transfer control and write data file. (Refer to the Block Transfer
Buffer Layout section for details on control information.
2. The scanner reads the BTW data and control data from the MO
file. One byte of the scanner’s I/O image file is used for
handshake purposes. Note that the SLC user program must
never read or write to this image space.
In this example, Logical Rack 3, Logical Group 7, Logical Slot 1 is used.
Chassis Backplane
One byte is consumed from the
input and output image file for
"handshake" purposes.
I/O
Image
1747 RIO
Scanner
M
Files
RIO Link
Adapter or
Intelligent I/O
Module
SLC 5/02
(or above)
Processor
M0 file
M1 file
= path of the BTW
Input
Image Output
Image
Slot 1
Slot 0
Slot 1
Slot 0
Logical
Rack 0
Logical
Rack 3
Group 0
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 0
Group 1
Group 7
Group 0
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Word 0
Word 1
Word 2
Word 3
Word 4
Word 5
Word 6
Word 7
Word 8
Word 9
Word 23
Word 24
Word 25
Word 26
Word 27
Word 28
Word 29
Word 30
Word 31