Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 117)

Publication 1747-UM010B-EN-P - September 2003
RIO Block Transfer 7-5
3. The M1 file contains BTW status information. Refer to the Block
Transfer Buffer Layout section for details on status information.
4. The RIO scanner transfers BTW information across the RIO link
to the adapter.
5. The adapter transfers the BTW information to the appropriate
adapter or intelligent I/O module.
RIO Block Transfer General
Functional Overview The RIO scanner performs block transfers through control/status
buffers that you allocate in the scanner’s M0 and M1 files. For BTWs,
the M0 BT buffer contains BTW control data and BTW data, while a
corresponding M1 BT buffer contains only BTW status information.
For BTRs, the M0 BT buffer contains only BTR control data, while a
corresponding M1 BT buffer contains BTR status information and BTR
data. Block transfers occur asynchronous to RIO link discrete
transfers. Block transfers occur as RIO scan time allows – discrete I/O
transfers have first priority.
A total of 32 block transfer control/status buffers exist in the M0
(output/control) and the M1 (input/status) files.
Block transfer buffers consist of:
•
3 BT control words in an M0 file BT buffer
•
4 BT status words in an M1 file BT buffer
•
64 words of BTW data in an M0 file and 64 words of BTR data in
an M1 file. Refer to the diagrams on the following pages.