About Upload

A project file contains:
  • Controller and I/O configuration information
  • Program logic
  • Data definitions
  • Documentation (for example, rung comments and descriptions for tags, tasks, programs, routines, modules, and user-defined data types)
When loading a project into a controller, most of this information is loaded into the memory of the processor; the exception is the documentation, which is maintained offline in the disk file.
When uploading a project from a controller, the
Logix Designer
 application merges the documentation in the project file on a disk with the information from the controller. This process ensures that the comments and descriptions are associated with the corresponding objects uploaded from the controller.
However, there is still some information that is not stored in the controller that is lost. This is limited to:
  • References to tags in user logic (ladder diagram only)
    For example, given a ladder diagram logic reference to:
    MyAccBit0, which aliases MyTimer.Acc.0
    MyAcc, which aliases MyTimer.acc
    Then, after an upload:
    MyAccBit0, which aliases MyAcc.0
    MyAcc, which aliases MyTimer.acc
    However, given a ladder diagram logic reference to:
    MyTimer.Acc.0
    MyTimer.acc
    Then, after an upload, a ladder diagram logic reference to:
    MyAccBit0, which aliases MyTimer.Acc.0
    MyAcc, which aliases MyTimer.acc
  • The operands used in instructions (this information is not stored in the controller)
Upload uses a technique referred to as "best fit" to reconstruct instruction operands. For example, given the alias chain described in the previous example, if have an OTE instruction whose operand is MyTimer.acc.0, after an upload, the operand would be MyAccBit0.
Only Upload into a project file that matches the project in the controller. The projects match if the two are related in one of the these ways:
  • The project file was downloaded to or uploaded from the controller, OR
  • The project file is a copy of the project file that matches the project in the controller
    TIP:
    Disallowing Upload with a project file that does not match helps prevent accidental loss of project documentation. If preserving documentation in the project is not important, to upload a project file over project documentation, first delete it via Windows Explorer or a similar file management tool, or from the
    Select File
    dialog box.
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