The .APB, .NDL and .NXE files are downloadable application images files produced by NodeBuilder.
The .NXE file is used to support legacy network tools and is usually not required. We don't recommend using the NXE file to download your application if either the NDL or APB file is available. This is because the NXE file does not contain important information such as network variable table.
The .APB file is created from the .NXE file and .XIF file. This is the file used by an LNS application -such as LonMaker or OpenLNS CT- when loading the device.
The .APB files cannot be used to update a device's communication parameters or the clock multiplier for a 5000 Series chip.
The .NDL file is used to support manufacture-time loading of devices with the NodeLoad utility. If you change the device's communication parameters or the clock multiplier for a 5000 Series chip, you must load the communication parameters contained in the .NDL file. See HOWTO: Load new communications parameters into a device (KB1001) for instructions.