Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 316)

Chapter
Call Routines 69–127 13
13 -58
Important: This call requires the BASIC module jumper JW5 to be in 16
point mode (page 1 -7).
Use CALL 122 to read up to 63 words of data from a remote DF1 node
(PLC-2, -3, or -5) to the BTW buffer, and/or a string within the BASIC
module.
This table lists specific notes when using CALL 122 with the PLC-3 and
PLC-5 processor.
PLC processor Notes
3 for timers and counters, the file number pushed (third
parameter) is the structure number, limited to a maximum of
255 words
5 for timer data, an element is three 16-bit words, stored in the
destination file in the following order: Control, Preset, and
Accumulator
If you choose an internal string, the first character (transaction number)
increments upon a successful read transaction to inform the BASIC module
that new data is in the string. The value of the transaction number wraps
around from 255 to 0.
Set up the DF1 port parameters with CALL 108 (page13 -38). The DF1
port can operate with full-duplex or half-duplex slave protocol. Also make
jumper JW4 is configured for DF1 protocol (page 1 -6).
Execute CALL 122 once to set up the data transfer parameters.
PLC input table bit 12 and output table bit 12 is used to initiate and notify
completion of transfer.
1. The local PLC processor sets the output image table bit 12 to inform
the BASIC module to execute the READ command configured in this
call.
PLC Processor
Set Output Image
Table Bit 12
BASIC Module
PLC Backplane
PRT2
PRT1
CALL 122: Read Remote
DF1 PLC Data File