CAUTION
Unusual changes to variable values in an application which is currently running on the controller can cause undesired behavior of the controlled plant.
Evaluate possible dangers before forcing variable values, and take the respective safety precautions. Depending on the controlled plant, this could result in damage to the plant or the workpieces, or injury or death of personnel.
In CODESYS, variable values in the PLC can be changed in online mode. Here we make a distinction between forcing and writing a previously prepared value.
Writing is done with the “Write Values” command ([Ctrl]+[F7]) and sets the variable to the prepared value one time. In this way, the value can be overwritten again by the program at any time.
Forcing is done with the “Force Values” command ([F7]) and sets the prepared value permanently. For more information, see below.
The preparation of a value for forcing or writing is possible at different places:
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Declaration part: “Prepared value” field
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Implementation part of the FBD/LD/IL editor: inline monitoring field
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Watch view: “Prepared value” field
For instructions about this, see below. In the case that you want to prepare a value again for an already forced value, the “Prepare Value” dialog opens with options for handling the current force value.
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Functionality of forcing
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Forcing in the declaration part
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Forcing in the implementation part
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Viewing and editing all forced variables one list
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Forcing a function block input in CFC