Rockwell Automation 6008-SV2R VMEbus remote I/O Scanner - Manual (Page 48)

Chapter
Communicating with Remote I/O
4
4Ć11
Figure 4.7
BlockĆtransfer sequence - receiving data from a completed transfer
VME
master
processor
On the previous adapter scan, the scanner sent a block
transfer request. During this scan, the adapter returns the
response data to the scanner.
scanner
The application program must move the blockĆtransfer
data out of the general memory area and clear the
semaphore so other blockĆtransfers can be completed.
1771 I/O
chassis
adapter
#n
input
modules
output
modules
BT#n
❺
❻
BT
data
The scanner:
1.
tests and sets the semaphore
2. places the blockĆtransfer data in the general data area
3.
places a completion code in the confirmation area
4. provides the proper blockĆtransfer tag number
5.
generates a VME interrupt (optional)
BT
data
scanner's global RAM
BT#n
BT
data
❹
scan n + 1