d memory is exhausted, a message will appear before executing an online change (Online Change). The remaining reserved memory can also be monitored at any time from the interface where the reserved memory is configured.
Configuring Memory Before Initial Download: It is advisable to configure the reserved memory for function blocks before downloading the PLC project to the controller for the first time. If reserved memory is configured after the PLC project has already been downloaded to the controller, complex online changes (Online Change) may be required.
Other Configuration Options: Besides the Online Change Memory Reserve settings window, the reserved memory for each function block can also be configured in its Property window. To do this, the function block must be selected in the project tree.
Setup Method:
To accommodate potential significant modifications to the function blocks in the project in the future, it is necessary to copy the function block instances to another storage location during an online change (Online Change). Ideally, the currently open project should not have been downloaded to the controller yet.
- Navigate from the main menu to PLC > Windows > Online Change > Online Change Memory Reserve Settings.
The Online Change Memory Reserve view will open. - Select the PLC project from the selection list and then Scan Application.
- Select the Function Block for Which to Configure Reserved Memory
If the application has not yet been installed on the controller, you can edit the input field "Memory reserve (in bytes)".
If a PLC project already exists on the controller, you need to click the "Enable" button first. Note that if reserved memory for a PLC project already exists on the target controller, you must copy all instances of the affected function blocks in memory. - Enter the size of the memory reserve in bytes and click "Apply for selection".
The number of bytes entered will be displayed in the Memory Reserve field in the main window table. Additionally, the table will automatically update with the "Size", "Instance Count", "Additional memory for all instances", and "Remaining size of memory reserve".
- Download the PLC project to the controller.
The function block instances occupy the currently required memory as well as the additional reserved memory. Thus, significant future modifications to the function blocks can be loaded into the controller via online changes (Online Change) without the need to recopy all instances of the function blocks in memory.