Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 120)

Sample Programs
Appendix A
A-2
Table A.A
Data Files
This information: Is in file:
BTR and BTW control files and storage words N30
BTR data files (this is where the 1785-BCM module sends
BTR data) N31
BTW data files (this is where the 1785-BCM module
obtains BTW data) N32
Buffered data from the primary processor that you want to
timers, counters, devices, etc. N33
(secondary program only)
Data you want to send to the secondary processor, e.g.,
timers, counters, devices N34
(primary program only)
Important: Data in file N33 in the secondary processor is identical to data
in file N34 in the primary processor.
Figure A.1 shows how these files relate to the transfer of data from the
primary to the secondary systems.
Figure A.1
File Relationship to Transfer of Data
N34 N32 N31 N33
Primary Processor Secondary Processor
Primary
1785-BCM Secondary
1785-BCM User ladder
program moves
timers, counters,
devices, etc. User ladder program
moves timers,
counters, devices
etc.
11678I
Program File Organization
In the sample program method 1, we use 4 program files. Program file 2
contains the main program. This program:
determines if the processor is primary or secondary
executes BTR and BTW instructions