Get and Set System Data

The controller stores system data in objects. There is no status file, as in the
PLC-5
 controller. Use the GSV/SSV instructions get and set controller system data that is stored in objects:
  • The GSV instruction retrieves the specified information and places it in the destination.
  • The SSV instruction sets the specified attribute with data from the source.
Attention: Use the SSV instruction carefully. Making changes to objects can cause unexpected controller operation or injury to personnel.
To get or set a system value:
  1. Open the
    Logix Designer
     application project.
  2. From the
    Help
    menu, click
    Contents
    .
  3. Click
    Index
    .
  4. Type
    gsv/ssv objects
     and click
    Display
    .
  5. Click the required object.
    To get or set
    Click
    axis of a servo module
    AXIS
    system overhead time slice
    CONTROLLER
    physical hardware of a controller
    CONTROLLERDEVICE
    coordinated system time for the devices in one chassis
    CST
    fault history for a controller
    FAULTLOG
    attributes of a message instruction
    MESSAGE
    status, faults, communication path, and mode of a module
    MODULE
    group of axes
    MOTIONGROUP
    fault information or scan time for a program
    PROGRAM
    instance number of a routine
    ROUTINE
    properties or elapsed time of a task
    TASK
    wall clock time of a controller
    WALLCLOCKTIME
    time synchronization status of a controller
    TIMESYNCHRONIZE
  6. In the list of attributes for the object, identify the attribute that you want to access.
  7. Create a tag for the value of the attribute.
    If the data type of the attribute is
    Then
    one element (e.g., DINT)
    Create a tag for the attribute.
    more than one element (e.g., DINT[7])
    Create a user-defined data type that matches the organization of data used by the attribute. Then create a tag for the attribute and use the data type you created.
  8. In your ladder logic routine, enter the appropriate instruction.
    To
    Enter this instruction
    get the value of an attribute
    GSV
    set the value of an attribute
    SSV
  9. Assign the required operands to the instruction.
    Refer to the GSV/SSV instruction for information on these operands.
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