When we need to add a new Profinet slave device (such as IO, gateway, servo drive, etc.) to the Profinet bus, we first need to obtain the GSD file of the slave device, and then import it into the Profinet master programming software (such as STEP 7 -MicroWIN SMART (supported by v2.4 and above), TIA Portal, codesys, etc.) can configure the corresponding slave device into the profinet network. And the related resources of the slave device can be accessed through the Profinet bus. So what is a GSD file and what information does it contain from the slave station?

  1. What is a GSD file?

The GSD file is the General Station Description file. It is a formatted technical description file for data transmission and engineering applications of profinet fieldbus equipment. It mainly contains the following information:

- Communication parameters, communication capabilities

- Device structure (for communication-related cases: modules, submodules)

- Directory information (device description,... )

- Structures for looping data and boosting parameters

- Definition of diagnostic information (alarms only)

- Project information (icons, pictures, text, values)

- Order number (for selection and order processing)

But does not include:

- Complex user interface (graphs, charts, wizards)

- Dependencies (for example, dependencies between IO data)

- Complex slot rules

- Application diagnostics

- Device specific business logic

- Mechanical data, connection diagrams

The GSD file and the information it describes are the only source for the master station to obtain profinet communication-related information from the slave device. Therefore, the GSD file is installed once in the programming software. The field device is then configured e.g. from the product catalog of the engineering tool

  1. What is GSDML?

A GSD file is an XML file that can be created and processed using standard tools. GSDML is the descriptive language of GSD files. It defines multi-layer device attributes, so it is very suitable for improving the hierarchical description of field devices. The image below shows the general part of a simple GSD file for field device identification.

  1. GSD file structure

Profile Header: General profile information, such as profile name, profile version, and profile publisher, are all stored in the profile header.

- Profile Body: The actual field device data is located in the profile body. It contains information for unambiguous identification, indicates the product family to which the device belongs, and describes all communication properties of the field device. Depending on the functionality and structure of the device, this main section of the GSD file can be very extensive, as it contains the following information:

lCommunication capability-communication ability

lConfiguratio-Configuration information



lDiagnosis-Diagnostic information

lreferences to graphics and text-references to graphics and text

  1. Summary

Generally, the GSD file contains a basic description of profinet equipment:

Conformance Classes: class A, class B, class C

Application Classes: class 1 (RT), class 2 (IRT), class 3 (IRT)

PhysicalSlots: available slots and subslots

DeviceAccessPointList: device access point information

ModuleList: The definition of module model, including IO data length and data type, slot rules, etc.

RecordDataList: parameterized configuration of the module (optional)

SubmoduleList: Definition of submodule model, including IO data length and data type, subslot rules, etc.