The Online Change command is by default available in the Online menu for triggering an online change on the current active application (Set Active Application). It is also available in the contextual menu of the application which is currently selected. Here it allows you to trigger an online change on exactly this application even if it is not the currently active one.
Online change means that only the modified parts of an application program already running on the controller are reloaded. This is not possible after a clean all or clean operation. The cleaning process removes the compile information which is automatically stored at each code generation and which is the basis of an online change.
The Online Change command modifies the running application program and does not affect a restart process. The program code can behave other than after a complete initialization because the machine keeps its state. Pointer variables keep their values from the last cycle. If there is a pointer on a variable, which has changed its size due to an online change, the value will not be correct any longer.
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UNINTENDED EQUIPMENT OPERATION |
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oMake sure that the new application code nevertheless will affect the desired behavior of the system. oMake sure that pointer variables are reassigned in each cycle. |
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Failure to follow these instructions can result in death, serious injury, or equipment damage. |
During online change, the Details dialog of the message box lists - among the usual information on the download process - also the changed interfaces, the concerned variables, and the objects for which new code has been generated. If data location changes, a message is displayed indicating that issues may occur referring to the use of pointers.
NOTE: In the Memory Reserve for Online Change view, you can configure memory reserves so that instance variables do not have to be moved in memory when changing a function block during an online change.
Keep in mind that an online change will automatically be offered when you are going to log in on a controller with an application program which is already running there, yet has been modified since the last download.
An online change (partial download) initiated while the controller is in the RUNNING state returns the controller to the RUNNING state if successful and provided the Run/Stop input is configured and set to Run. Before using the Login with online change option, test the changes to your application program in a virtual or non-production environment and confirm that the controller and attached equipment assume their expected conditions in the RUNNING state.
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UNINTENDED EQUIPMENT OPERATION |
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Always verify that online changes to a RUNNING application program operate as expected before downloading them to controllers. |
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Failure to follow these instructions can result in death, serious injury, or equipment damage. |
NOTE: Online changes to your program are not automatically written to the Boot application, and will be overwritten by the existing Boot application at the next restart of the controller. If you wish your changes to persist through a restart, activate the option Implicit boot application on online change in the View > Properties dialog box, or activate the option Update boot project in the online change dialog box.
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