In the introductory course, we introduced the major data file types available in the PLC.
Output file 0 and Input file 1 are defined to hold values from physical I/O cards.
B3 represents a binary file.
Each of these three file types can be addressed by word, such as B3:1, or by bit reference, such as O:0/15.
Data files for timers, counters, integers, and floating-point types were also covered in the introductory course, and we showed how additional data files can be created in addition to the default files. We also added symbols and descriptions to the addresses used in the BALLMILL program.
In the BALLMILL program we developed in the introductory course, we demonstrated how to add and duplicate rungs of ladder logic, create program branches, and add ladder page and rung comments.
We created a second program file which was called when we needed to scale an analog value. We demonstrated the use of the JSR or Jump To Subroutine instruction to divert execution to Program File 3 in the BALLMILL example.