Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 326)

Chapter
Call Routines 69–127 13
13 -68
6. The BASIC module clears bit 13 in the input image table.
PLC Processor
Clear Input Image
Table Bit 13
BASIC Module
PLC Backplane
PRT2
PRT1
7. The BASIC module assembles the DF1 packet and sends it to the
remote device.
Remote Device
DF1 Packet
BASIC Module
PRT2
DF1 Network
8. The BASIC module places the DF1 status of the transaction in BTR
word 1.
PLC Processor
BASIC Module
PLC Backplane
BTR Buffer
DF1
Status
Reserved
9. The BASIC module sets the input image table bit 4 to inform the PLC
processor that the data was transmitted, and that the status of the
transfer is valid. The PLC processor performs a block transfer to
retrieve the status.
PLC Processor
BASIC Module
PLC Backplane
Set Input Image
Table Bit 4