A building management system includes a programming tool and a target device. The graphical tool includes a user interface generator configured to provide a user interface that allows a user to create a block design comprising a plurality of logical, mathematical, and functional object. The target device includes a block generator configured to receive a text file of the block design, convert the text file into an application block file, and assemble the application block file into a custom application for the target device. The target device further includes a device controller configured to execute the custom application to modify the behavior of the target device.