What is a GSD file in TIA portal

Explain the GSD file in the TIA portal

These are files that are supplied by other parties to be seized via Siemens TIA. Think of controlling a frequency regulator. You get the function blocks needed for control. GSD file has got nothing to do with TIA, in fact, every device which communicates on Profibus needs a GSD file, and bear in mind Profibus is an open platform not only for siemens. simply put a GSD file is a text file that describes your device for it to be configured on Profibus DP