Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 317)

Chapter
Call Routines 69–127 13
13 -59
2. The BASIC module issues the appropriate READ command to the
remote PLC. The data and status are received from the PLC
processor.
Remote PLC Processor
DATA FILE
BASIC Module
READ command
PRT2
Data and Status
DF1 Network
3. When data is available, the BASIC module transfers the data into the
BTR buffer and the BASIC module places the transaction status in
the lower byte of BTR buffer word 1. The upper byte of BTR word 1
is reserved.
BASIC Module
Data 2–64
BTR Buffer
Status 1 Reserved
4. The BASIC module sets the input image table, bit 12 and performs a
block transfer read.
PLC Processor
BASIC Module
PLC Backplane
Sets Input
Image Table
Bit 12