Force a Variable

At runtime, all variables in the table widget are animated 1 To better track variables and expressions of the PLC programs in test mode, the KAS-IDE dynamically computes their value along with the execution and displays the result with real-time values.

At runtime, double-click on the value of the variable in the list or press the ENTER key when it is selected.

A popup window appears and allows you to Force, Lock, or Unlock a variable.

Force

• Change the value of the selected variable.
• Depending on the variable type, you have the possibility to define its value either in the text field or with the check boxes. (Figure 1)



Figure 1: Forcing a variable

Lock

• Variables, member variables of a structure and variables in an array may be locked.
• When a variable is locked, its value is no longer changed by the runtime.
  • You can then force its value from the debugger independently from the runtime operations.
• All variables can be locked and forced at runtime.

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• The value of a locked variable is displayed with square brackets. (Figure 2)
  

  

• Figure 2: Example: Lock variable

The variable locking feature can be enabled or disabled via the PLC Options device toolbar button.

If enabled, the Lock and Unlock buttons are accessible (Figure 4):

Figure 3: Enabled locking

If disabled (default), the Lock and Unlock buttons are not accessible (Figure 3):

Figure 4: Disabled locking

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• If PLC variable locking is enabled, the controller Runtime requires an additional 3% to 10% CPU processing power to manage the PLC variable locking.
  For the best controller performance, disable PLC variable locking.

Unlock

• Remove the lock on a variable so that it can be changed again by the runtime.