Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 104)

Publication 1747-UM010B-EN-P - September 2003
6-8 Module Control and Status Word
Data Transfer Status Word
Data Transfer Handshake
Word The Data Transfer Handshake Word (DTHW) is used in the data table
transfer from primary to the secondary system. Each bit corresponds
to a block in the 1747-BSN module.
When the secondary 1747-BSN receives a new block from the primary
system, it writes the block to the M1 area to be read by the secondary
SLC 5/0x. The secondary 1747-BSN also sets its corresponding bit in
DTSW to advise that this new block is ready to read. After reading the
block, the SLC 5/0x must set the corresponding handshake bit in
DTHW. Then the 1747-BSN module clears the bit in DTSW.
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
14
0
15 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Block # 1
Block # 2
Block # 3
Block # 4
Block # 5
Block # 6
Block # 7
Block # 8
Block # 9
Block # 10
Block # 11
Block # 12
Block # 13
Block # 14
Block # 15
Block # 16
DTSW (M1:s.3410)