Topic: DMD0271
Compare Programs
This utility will compare the code-blocks of the currently opened project to the code-blocks in a project in a different location. This operation DOES NOT compare the element documentation, the rung comments, or the System Configuration, it only compares the ladder logic in the code-blocks and the code-block's configurations.
When Do-more Designer establishes an online session, it will automatically run the Compare Programs utility to compare the code-blocks in the controller with the code-blocks in the project. Compare Programs can be run manually by selecting it from the Tools-> Compare Programs... menu selection.
Select one of the following options specify the location of the project to compare to.:
Select Another Program and use the Browse... button to locate the project on disk that and then compare the code-blocks of the currently opened project to the code-blocks in that project.
Select What's on the Disk to compare the code-blocks of the currently opened project to the code-blocks in the project that is saved on disk.
Select What's in the PLC to compare the code-blocks of the currently opened project to the code-blocks in the Do-more controller that is currently online.
The Include hidden Edge Bit and Instruction ID parameters as part of comparison is typically not enabled. This is because Edge Bits
Edge Bits hold the scan-to-scan state of the edge-triggered inputs. The value of an Edge Bit is assinged when the project is downloaded to the CPU. Edge Bits are automatically added to the project by Do-more Designer and are for internal use only. and Instruction IDs
This only becomes an issue for the user when the CPU assigns new values to the Edge Bits or Instruction IDs during a project download and renders the online and offline copies of the projects different. If this happens you will see the Write to Disk icon become re-enabled, and a dialog box will be displayed asking if you want to save the updated copy of the project to disk or not. If you select Yes the updated Edge Bit and Instruction IDs will be saved to the offline copy of the project. If you choose NOT to save to disk at this time the offline and online copies will remain different, the Write to Disk icon will remain enabled, and you will see Program differences the next time you connect to your PLC with your offline copy of the project open.
Click OK to start the comparison.
Click Cancel to exit without comparing the projects.
Once the comparison is complete, the programmer will see a dialog that lists the differences between the two projects. The top section of the dialog lists the differences between the code-blocks at the project level, specifically looking for code-blocks that are missing from one of the projects or code-clocks that have a different execution order.
Use the following four options to control what differences are displayed in the list:
Show code-blocks only in <current project> - lists the code blocks that only appear in the currently opened project.
Show code-blocks only in <other project> - lists code-blocks that only appear in the other project.
Show code-blocks only in different execution order - lists the code blocks that have a different execution order.
Show code-blocks only in consistent execution order - lists the code blocks that have the same execution order.
The bottom section lists the differences in the ladder logic contained in the code-blocks.
Differences between the ladder logic instructions are displayed in the following color-coded ways:
Instructions that are NOT different are displayed in Black.
Instructions that are Different are displayed in Blue.
Instructions that are in the Current Project but not in the Other Project are displayed in Green.
Instructions that are in the Other Project but not in the Current Project are displayed in Red.
If Edge Bits
Differences in Edge Bits will be shown as a /Exxx after the instruction.
Differences in Instruction IDs will be shown as a /Ixxx after the instruction.
The Instruction Differences - lists the code blocks and the addresses of the instructions in the code-block that are different. Clicking on an entry in this list will display the comparison details of that address in the details window.
The Previous and Next buttons will move backward and forward respectively through the program one instruction at a time.
The details window displays the ladder logic instruction mnemonics of the two code-blocks being compared, with the two left-most columns showing the address and mnemonic from the Current Project, and the two right-most columns showing the address and mnemonic from the Other Project.
The following three options define the level of detail that is displayed
in this list:
-
Show Differences Only - only displays the address and mnemonics that are different.
-
Show Differences w/Context - displays the one address and mnemonic before and after each of the differences.
-
Show All Rungs - display all of the rungs in the code blocks.
See Also:
Resolve Online / Offline Differences