Rockwell Automation 1747-PTxx Getting Started Guide for HHT - Manual (Page 19)

Chapter 2
Control Basics
2–2
Program Files
Program files contain controller information, the main control program, and
any subroutine programs. The first three program files are required for each
program. These are:
•
File 0
This file stores the controller configuration and other system information.
•
File 1
This file is reserved for internal controller use.
•
File 2
This file stores the main control program.
•
Files 3 – 255
These files are optional and used for subroutine programs.
Most of your work with program files will be in file 2, the main program file.
This file contains your ladder logic program that you create to control your
application.
Data Files
Data files contain the data associated with the program files. Each program
can contain up to 256 data files. These files are organized by the type of data
they contain. Each piece of data in each of these files has an address
associated with it that identifies it for use in the program file. For example,
an input point has an address that represents its location in the input data file.
Likewise, a timer in the timer data file has an address associated with it that
allows you to represent it in the program file.
The first 9 data files (0 – 8) have default types. You designate the remainder
of the files (9 – 255) . The default types are:
•
File 0 – Output Data
This file stores the state of the output terminals for the controller.
•
File 1 – Input Data
This file stores the status of the input terminals for the controller.
•
File 2 – Status Data
This file stores controller operation information.
•
Files 3 – 7
These files are pre–defined as Bit, Timers, Counters, Control, and Integer
data storage, respectively.
•
File 8
This file is reserved for internal use.
•
Files 9 – 255
These files are user–defined as Bit, Timer, Counters, Control, and Integer
data storage.
Most of your work with data files will be in files 0 and 1, the output and
input files. Refer to appendix A for an example of the Timer data file.