1.7.3. I/O Configuration

As I/O configuration it is called the complete set of mechanisms, to support all hardware-devices and I/O 2 systems that are connected to a controller (the runtime system). This includes the description of the hardware hierarchy, description and parameterization of each device and the support of each device with a driver (I/O-driver).

One of the main aims of the I/O-configuration in CODESYS V3 is internal standardization of the different device types, so that different field bus nodes, internal I/Os, extension modules, drives, etc. are basically treated in the same way. This means that each device is described with the identical description structure. So a driver can interpret principally every device description.

The second main issue is that the I/O-configuration is created as an IEC data-structure and is downloaded to the runtime system with the IEC application that includes the I/O-configuration.

If you want to access the I/O-configuration from another IEC application, this application must be a child application of the application with the I/O-configuration.

In the following chapters, all themes to access devices and IOs are described in detail.

  • Version (string): Indicates the version of a device description.
    Here too the string enables a variable format for importing alternative description formats. For all types >= 0x1000 the format is specified as follows:
    n.n.n.n
    with “n” representing any decimal number, e.g. “1.0.17.3”.
    Within a device description it is possible to describe further modules that are only used in the context of this device description. In principle they are described and used in the same way as a device, although they can only be used as a child of the main device or another module defined in the main device. Modules are identified through the device identification together with an additional module Id.
  • Module Id (string): Identifies a module within a device description.
    The format is not free.
2

I/O: Input- and Output-Signals (Digital- or Analog), e.g. Sensor Data