Communication Protocols
Copyright IXXAT Automation GmbH
85
IEM Manual, 1.5
5 Communication Protocols
In this chapter protocol specific items are described.
5.1
PROFINET
5.1.1 Device Description File
A template of a device description file (GSDML-File, General Station Descrip-
tion) for the IEM is included in the software package. The GSDML provides
information about the device configuration data [PNIO1].
To modify the Device Description File to your own behavior you can refer the
manual from Siemens “GSDML – Getting Started” [PNIO2].
5.1.2 PROFINET device model
In order to get familiar with data addressing in PRO
FINET it’s good to get an
overview of the PROFINET device model. There are two types of devices:
Compact devices: the internal structure of the device is fixed by the pro-
ducer and cannot be changed and adapted for future applications;
Modular device: the internal structure of the device can be customized dy-
namically when configuring the system.
Nevertheless, data within both of the above mentioned devices can be ad-
dressed using the following hierarchy:
Slot:
it is a physical, in case of a modular device, or a virtual, in case of a
compact device, slot in an I/O field device in which a module described in
the GSDML-file is placed.
Subslot:
within a slot, it represents the actual interface to the process (in-
puts/outputs) by means of a submodule that is plugged in according to the
GSDML-file. The granularity of a subslot (bitwise, byte wise or word wise)
is determined by the application itself. For addressing of the cyclic data the
couple “slot-subslot” is sufficient.
Index:
specifies the data within a slot/sub slot that can be accessed acyclic
using read/write services (e.g. parameters, manufacturer- specific data,
Identification and Maintenance Profile (I&M) functions).
Since PROFINET transfers the data as a bit combination between provider
and consumer without any interpretation, it makes sense to introduce an addi-
