The General Station Description (GSD) is the definition of certain properties of PROFINET Devices which are of interest for engineering tools, such as IO Data, IO Channels, Parameters and Alarms. The format defined for the GSD is the GSDML.

The General Station Description Markup Language is an XML-based description language for PROFINET Devices (see [GSDML]).

Data, which a Device cyclically receives from the Controller and which controls the Device application or the peripherals.

Data, which a Device cyclically sends to the Controller.

For Devices, all Input and Output Data (cyclic transmission).

An IO Channel is an entity of the Submodule where digital or analogue electric signals are generated (output) or converted into digital values (input). A Submodule’s IO Data may be organized using several IO Channels.

Acyclic Data about errors, maintenance status, application specific process alarms, incidents like pull/plug, updates and the like yielded by the Device.

Initial setting written to a Device with a parameter record during its start-up phase.

Access to Parameters via the “Base Mode” as described in [PDP], sec. 6.2.3. Requests and replies are transmitted by use of the “Acyclic Data Exchange” mechanism of the communication system, which usually implies writing and reading PROFINET records.

Additional data value (sensor data as ambient temperature, welding current, and the like) or Parameter which is yielded by a Device. The data value can either be read from a Submodule using the associated PROFINET record index or obtained as Parameter using BMP Access. Vendors might allow write access to certain data values (see 6.7).

A Device is a separate addressable unit exchanging IO Data with a Controller. Devices are usually configured by the Controller and may also generate acyclic data like Alarms or diagnostic information. A Device may consist of several modules and Submodules. The IO Data, the Parameters, the Alarms, and the Data Objects of a Device are described in the GSDML file.

A Controller is a host running a program which reads and writes the IO Data of one or more Devices.

A PN Submodule is the consumer or the provider of one Telegram and the addressable endpoint for PROFINET access.

An Application Relation contains the communication channels for cyclic data exchange (IO Data CR), acyclic data exchange (Record data CR) and alarms (Alarm CR). These CR’s are established by the Controller during the start-up phase of the Device using the configuration data created by the engineering tool.

The NameOfStation is the name of the communication interface determined by the configuration assigned to the Device by the Controller. One Device can have more than one communication interface.