Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 240)

Chapter
Call Routines 0–68 12
12 -50
Important: This call requires the BASIC module jumper JW5 to be in 16
point mode (page 1 -7).
Use CALL 50 to write up to 63 words of data from the BTW buffer and/or
a string within the BASIC module to the remote DH-485 file at the node
address you designate.
This call is useful for writing to a display device directly from the PLC
processor or an internal string. Once you set up and enable this operation,
it is performed transparently in the background while the BASIC module
executes a BASIC program in the foreground.
Refer to the DF1 Protocol and Command Set Reference Manual
(publication number 1770-6.5.16) for detailed information on DH-485.
If you choose an internal string, the first character (transaction number)
increments on successful completion of the write to inform the BASIC
module that data was sent. The value of the transaction number wraps
around from 255 to 0. Execute CALL 50 once to set up data transfer
parameters.
1. Local PLC processor ladder logic builds a file with the DH-485 data.
PLC Processor
DATA 2–64
Reserved Reserved
DH-485 Data File
2. The PLC processor latches output image table, bit 15 to inform the
BASIC module that data can be transferred.
PLC Processor
BASIC Module
PLC Backplane
Latch Output
Image Table
Bit 15
CALL 50: Write to Remote
DH-485 SLC Data
Tip