Rockwell Automation 1785-Lxxx Enhanced and Ethernet PLC-5 Programmable Controllers - Manual (Page 54)

Publication 1785-UM012D-EN-P - July 2005
4-10 Addressing I/O and Controller Memory
Understanding PLC-5
Controller Memory Controller memory is divided into two basic areas:
Storage Areas Description
Data All of the data the controller examines or changes is stored in files in data
storage areas of memory. These storage areas store:
• Data received from input modules
• Data to be sent to output modules; this data represents decisions made
by the logic
• Intermediate results made by the logic
• Preloaded data such as presets and recipes
• Control instructions
• System status
Program Files You create files for program logic, depending on the method you are using:
ladder logic, sequential function charts, and/or structured text. These files
contain the instructions to examine inputs and outputs and return results.