Copyright Goodheart-Willcox Co., Inc. 112 Programmable Logic Controllers: Hardware and Programming Database The Database section of the Reports portion of the dialog box has three options. These options are Address/Symbols, Instruction Comments, and Symbol Groups. The Address/Symbols option lists the instruction addresses and their descriptions. Only the processor addresses used in the ladder logic diagram are listed. The Instruction Comments option displays the instruction comments, which are comments used to describe the input/output instructions. Note that on the ladder logic diagram, the instruction comments will write over the address comments. This means that if an address has both an instruction comment and an address comment, only the instruction comment will be printed. The Symbol Groups option prints the list and description of the symbol groups. You can create symbols for each input/output device. From then on, you can use the symbol to place the input or output device. For example, you can create a symbol called PB0 for the input I:0/0. Then instead of typing I:0/0, you can simply type PB0 to place the input device in the ladder diagram. Program Files The Program Files section of the report option in the dialog box has two options. These options are the Program File List and Program Files. The Program File List option prints a list of the ladder logic diagrams. It always lists file 0, file 1, and file 2. As explained earlier in this chapter, file 0, or SYS 0, is used to hold the status bits or flag bits. These bits are S2, S3, S5, and such. File 1, or SYS 2, is reserved. Therefore, file 0 and file 1 are considered system files. File 2, or LAD2, contains the main ladder logic diagram. If the PLC project uses subroutines, then the project may have additional files with ascending numbers, such as file 3, file 4, and file 5. Therefore, in addition to file 0, file 1, and file 2, a PLC project can have file 3 (LAD3) through file 255 (LAD255), if there is enough RAM memory available on the PLC system. You should select this report option. The Program Files option displays the ladder logic diagrams of the files in the report. You should select this report option. Data Files The Data Files section has three options. These options are Data File List, Data Files, and Memory Usage. A Data File List specifies the list of data files available for your PLC project. The Data Files option allows you to specify which data file you want to include in your report or the range for which data file will be printed. Memory Usage specifies the range for which a data file should be printed. Memory usage specifies the range of all data tables used in the PLC project. Occasionally, you may want to select the Data File List and Data Files options. This data can be beneficial when you are troubleshooting the PLC system. Figure 6-35 shows how to select a report option in the Report Preview dialog box. 6.10 Using Utility Instructions to Save and Retrieve PLC Programs In this section, you will learn how to change the subfolder and the drive location of where you save the PLC project. You will also learn how to open or import existing PLC ladder logic diagrams. This section also discusses the options for automatically saving project files and creating a backup. To save the PLC project from the File menu, click Save As. From the Look In box, select the drive and subfolder to which you want to save the project file. Then, enter the name of the file in the File Name text box and click Save.