Allen Bradley

More in depth programming information and documentation is available at DO Supply covering a wider array of Allen-Bradley FAQ

Optimizing Performance

  • Logix controllers are optimized for the DINT and REAL data types. Use these data types to avoid conversion overhead and optimize performance.
  • You can optimize the communication performance of acquiring data from Logix controllers by consolidating multiple data values into a User-Defined Type (UDT) or array.
  • Indexed references to array elements add additional scan time overhead to the application. Use single dimension arrays whenever possible.

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Communications

  • Reserve 20% or more of the controller's memory to accommodate communications and changes in future Logix controller firmware releases.
  • Use rack optimized communication formats for digital I/O modules to minimize amount of controller memory and communications overhead associated with these modules.
  • Use the CPS instruction to provide buffering of communications and I/O data to minimize impact of asynchronous data arrival.

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Drives and Motion

  • RSLogix 5000 integrated motion supports camming, gearing, single-axis, and multi-axis instructions in Ladder Diagram, Structured Text, and Structured Text embedded in Sequential Function Charts.
  • Execute motion direct commands directly from the context menu for any configured motion axis. The motion direct commands let you control motion instruction execution without creating or adding logic. This can be useful when first commissioning an axis or drive.

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I/O Configuration

  • Module icons in the I/O Configuration folder change to indicate the module has faulted or the connection to the module has been interrupted.
  • To remove a yellow triangle warning symbol, first check the connection status. If the status is "Connection is not scheduled", re-open the RSNetWorx software. Return to RSLogix 5000 software and the yellow triangle should be gone.

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Add-On Instructions

  • To display the logic of an Add-On Instruction, select the instruction and use the context menu (right click) to open the logic.
  • You can drag an Add-On Instruction from the Controller Organizer into any language editor.
  • Copy an Add-On Instruction Definition from one project and paste into another to move that AOI and referenced AOIs in to the project.

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Routines

  • Logix supports four controller programming languages: Ladder, Function Block Diagram, Structured Text, and Sequential Function Chart.
  • To simultaneously display logic in multiple routines, select Window -> New Window and then arrange the windows manually. Or select Window -> Tile Horizontal.
  • Multiply the number of words in a PLC/SLC program times 18 to estimate the amount memory (in bytes) needed in a Logix controller.
  • To display context-specific instruction help, select an instruction or element and press F1.

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Tags, Data Types and Other Data

  • As you organize, add, or delete members of a User-Defined Data Type, the software adjusts the associated tag members and values accordingly so that remaining members retain their values.
  • In the tag browser, click the >> button to display the tag filter. Use the tag filter to display unused tags or tags of a particular data type.
  • The tag browser filters tags in some situations. If you don't see a tag you expect, change the tag filter.
  • In version 15, the Tag Editor added support for New Window.

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Tasks, Programs and Equipment Phases

  • An event task in Logix is similar to the processor input interrupt (PII) in the PLC-5. Multiple event tasks can exist in the controller, each configured to execute at the initiation of independent triggers.
  • A periodic task in Logix is similar to the selectable timed interrupt (STI) in the PLC-5. Multiple periodic tasks can exist in the controller, each configured to execute at independent rates.
  • Double-click on a state in an Equipment Phase to navigate to the logic for that state.

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Controller Projects

  • Whenever you go online using RSLogix 5000, changes made to controller are simultaneously made to a temporary copy of the project file (.ACD). Save makes these changes permanent. Therefore, an upload is only necessary to obtain the latest copy of the tag data in the controller.
  • Both Rockwell Automation and third-party sample projects are installed with RSLogix 5000. You can find them in the RSLogix 5000 Samples folder. These projects demonstrate program techniques and code that you can use to program select modules.

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Keyboard

  • Keyboard shortcuts are listed in the Online Help, under the "Navigating the Software" topic.
  • You can use Ctrl+Page Down and Ctrl+Page Up to move between tabs in a dialog or routine window.
  • You can use Ctrl+Tab and Shift+Ctrl+Tab to move between multiple RSLogix 5000 views.
  • You can use Ctrl+G to invoke the Go To dialog. The Go To dialog is convenient for navigating the software.

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