Rockwell Automation 1756-RIO ControlLogix Remote I/O Communication Interface Module User Manual - Manual (Page 134)

134 Publication 1756-UM534B-EN-P - November 2010
Appendix A Scanner Mode I/O Map
Block Transfer Input
In scanner mode, even if a module has only a block transfer write, you should
map the module to input and output data, so that the control and status data
gets mapped.
Block Transfer Read Structure-Input
Offset 0 bits 0…7 contain a free-running counter that increments each time a
block transfer read executes successfully on the RIO network. Based on
configuration of the 1756-RIO module and its RPI, it may be possible that the
controller may see this value increment by more than 1 count per program
scan.
The 1756-RIO module sets the BTR error bit, offset 0 bit 11, when an error
occurs executing a block transfer read. It clears the bit when the block transfer
read enable bit is reset in the corresponding BT control write structure.
When a block transfer read error occurs, offset 0 bits 8…10 contain Error
Codes .
When you execute a block transfer read in manual mode, the 1756-RIO
module sets offset 0 bit 12 to indicate that the block transfer read executed
successfully. The bit is reset when the corresponding BTR.EN bit is reset in
the BT write control file.
Offset 1 bits 0…7 contain a free-running counter that increments each time a
block transfer write executes successfully on the RIO network. Based on the
configuration of the 1756-RIO module and its RPI, it may be possible that the
controller may see this value increment by more than 1 count per program
scan.
The 1756-RIO module sets the BTW error bit, offset 1 bit 11, when an error
occurs executing a block transfer write. It clears the bit when the block transfer
write enable bit is reset in the corresponding BT control write structure.
When a block transfer write occurs, offset 1 bits 8…10 contain an error code.
When you execute a block transfer write in manual mode, the 1756-RIO
module sets offset 1 bit 12 BTW.DN to indicate that the block transfer write
executed successfully. The bit is reset when the corresponding BTW.EN bit is
reset in the BT write control file.
Word offsets 2…n contain the read data returned by the block transfer
module.
0 1 2 3 4 5 6 7 8 9
BTR Returned Read Data
1st
16-bit
Word
BTW
44821