# Capture Type Function Block ### Overview Capture type [function blocks](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks) (commonly refered to as *capture blocks*) allow the ability to catch data as it comes over the network and save it to a buffer file for future analysis. A host of options and parameters split across multiple tabs allow the function block to be tailored to any use case. These blocks allow anything from a simple manual capture of a small amount of data, to sophisticated setups that record precise message sets based on custom filtering and trigger logic. ### Applications Table 1 describes just a few of the many ways that capture blocks can be used. In each case the application is described and a brief summary is provided of the capture block settings that might be used in a setup; these are presented in the same order that capture block tabs appear. Of course these are only samples and settings can be combined in almost any way that is required. **Table 1: Sample applications of capture type function blocks** | Application Description | Buffer | Start Type | Stop and Trigger Options | Storage | | -------------------------------------------------------------------------------------------------------- | ---------------------- | -------------------- | ---------------------------------------------------------------------------------------------- | -------------------------------- | | Save current data in a large, unfiltered buffer, possibly triggered by a hotkey. | No filtering | Start Immediately | Collect in a circular buffer, with large buffer | Manual save | | Save a new buffer file at a periodic rate. (Warning: This can fill up storage if set up incorrectly!) | No filtering | Start Immediately | Collect in a circular buffer, with very large buffer | Save when expression is true | | Create a small, filtered buffer file, triggered by a joystick button. | Filtering | Manual Start | Collect in a one-shot buffer, with small buffer | Automatically save when complete | | Capture data before and after a hotkey click. | Filtering | Start Immediately | Collect before and after a manual trigger, with small buffer and large post-trigger buffer | Automatically save when complete | | Store a large amount of data before an event that occurs very quickly. | No filtering | Start Immediately | Collect before and after a trigger expression, with large buffer and small post-trigger buffer | Automatically save when complete | | Capture data that occurs between two events. | Filtering | Use Start Expression | Collect in a circular buffer, with large buffer | Save when expression is true | | Capture data filtered using a script, with start, trigger and save expressions for ultimate flexibility. | Filtering using script | Use Start Expression | Collect before and after a trigger expression, with mid-sized buffer and post-trigger buffer | Save when expression is true | ### Creating a Capture Block Create a new capture block by clicking the ![](https://cdn.intrepidcs.net/support/VehicleSpy/assets/function_block_toolbar_add.gif) button on the far left of the [function block toolbar](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks/function-blocks-toolbar) and then select **Capture** from the popup menu. Vehicle Spy will create a default capture block as shown in Figure 1, with the **Filter Tab** selected. ![Figure 1: Default capture block setup.](https://2396693198-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FlRJv2XDCMeZSU0VbeZlG%2Fuploads%2Fgit-blob-2c6a45ef6c086925e24704d74167c9a70ccd89cf%2Fcapture_block_default.png?alt=media) ### Renaming a Capture Block Like all function blocks, a new capture block will appear in the function block list near the top of the function block pane. The function blocks can be renamed by double-clicking on the default name (**Function Block 1**) and entering a more descriptive name. The name entered in the [function block list](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks/function-block-list) also appears in blue in the function block setup area for greater clarity. ### Capture Block Tabs As shown in Figure 1, capture type function blocks have their parameters divided into five tabs. The following is a brief description of these tabs with links to pages covering each in more detail: * [Filter Tab](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks/function-blocks-types/capture-type-function-block/capture-type-function-block-filter-tab): Allows you to specify filters to restrict which messages are captured by the block. * [Start Tab](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks/function-block-start-tab): This tab is common to all function block types and allows you to specify the block's Start Type and related options. * [Stop and Trigger](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks/function-blocks-types/capture-type-function-block/capture-type-function-block-stop-and-trigger-tab): In this tab you tell Vehicle Spy how much data to capture and how to capture it. * [Storage](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks/function-blocks-types/capture-type-function-block/capture-type-function-block-storage-tab): Here you decide when to save the captured data and what formats and options to use. * [Data](https://docs.intrepidcs.com/vspy-3-documentation/3.9.15/vehicle-spy-main-menus/main-menu-scripting-and-automation/function-blocks/function-blocks-types/capture-type-function-block/capture-type-function-block-data-tab): This is a read-only tab where you can view messages as they are being captured.