1.7. Device Description

A so called device description contains all information for a PLC needed by the CODESYS development system to manage this device (you can think about a printer driver description here). This device description can be installed in the device repository of CODESYS and then you can add this device in the device tree of a project.

Additionally a device description can specify an IO-device (like a fieldbus master, a slave, a local IO-module, etc.) with its IO-channels, connectors and all necessary information. This device description can be installed in the device repository of CODESYS too and afterwards you can add this module in the IO-configuration in CODESYS.

A device description has an XML format and the file extension is named “.devdesc.xml”. The XML format must follow a defined scheme (can be downloaded here device_description_schema as a chm-helpfile).

So every device description file has a typical structure:

<?xml version='1.0' encoding='UTF-8'?>
<DeviceDescription xmlns="http://www.3s-software.com/schemas/DeviceDescription-1.0.xsd" xmlns:ts="http://www.3s-software.com/schemas/TargetSettings-0.1.xsd">
    <Types></Types>
    <Strings></Strings>
    <Files></Files>
    <Device>
        <DeviceIdentification></DeviceIdentification>
        <DeviceInfo></DeviceInfo>
        <DriverInfo></DriverInfo>
        <DeviceParameterSet></DeviceParameterSet>
        <Functional></Functional>
        <ExtendedSettings></ExtendedSettings>
        <Connector></Connector>
    </Device>
</DeviceDescription>

In the chapter Basics we describe the basics (types, strings, files, etc.).

In the chapter Device we describe the device node for PLC’s.

And in the chapter I/O Configuration we describe the device node for IO-modules.