1747-6.22, Backup Scanner User Manual

5-70 Scanner Configuration and Programming
Publication 1747-6.22
Rung 2:0
To decrease program scan time, copy the first four words of the M1 file to a binary file and use
these addresses throughout the program to access block transfer done, error, data, etc.
information without interrupting the program scan many times.
| +COP±±±±±±±±±±±±±±±±+ |
|±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±+COPY FILE | |
| |Source #M1:1.100| |
| |Dest #B3:0| |
| |Length 4| |
| +±±±±±±±±±±±±±±±±±±±+ |
Rung 2:1
Examine B3/13 (B3: 0/13), an internal storage bit, to determine when a block transfer is done. Note that
examining multiple individual M-file bits directly (every scan) can measurably increase processor scan time
| BT DONE |
| B3 +COP±±±±±±±±±±±±±±±±+ |
|±±±±] [±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±+COPY FILE | |
| 13 |Source #M1:1.110| |
| |Dest #N10:0| |
| |Length 64| |
| +±±±±±±±±±±±±±±±±±±±+ |
|
Rung 2:2
Examine B3/12 (an internal storage bit) to determine if a BT error occurred. Buffer the BT status
from B3:3 if an error does occur.
| B3 +MOV±±±±±±±±±±±±±±±±+ |
|±±±±] [±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±+MOVE |
| 12 |Source B3:3| |
| | 0000000000000000| |
| |Dest N10:64| |
| | 0| |
| +±±±±±±±±±±±±±±±±±±±+ |
Rung 2:3
| |
|±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±+END+±±±±±±±±±±±±±±±±±±±±±±±±±±±±±|
| |
Important: If you are using an SLC 5/02 processor M file data
cannot be directly monitored. To monitor M files, you
must move the M file words into an SLC file that can be
monitored, e.g., an integer “N” file. SLC 5/03 or later
processors allow you to monitor M files directly.
However, do not address M file bits more than necessary
throughout your application program. The processor
accesses M files like immediate I/O. Therefore,
excessive addressing of M files can greatly increase SLC
processor scan time. For more information on M files,
refer to Appendix B.