Glossary · Industrial communication
PROFINET IO controller
Also known as: IO controller, PROFINET controller
German: PROFINET-IO-Controller
In PROFINET, an IO controller is the device, usually a PLC, that establishes application relations with the configured IO devices, assigns their IP addresses by device name, sends them output data and receives their input data cyclically.
- Industrial communication
- Standards
In one sentence
A PROFINET IO controller, usually a PLC, connects to the configured IO devices and exchanges their cyclic input and output data.
Example
On a packaging line, the line PLC acts as PROFINET IO controller for the filler's remote I/O, the labeler's drives and the case packer's valve terminal, updating their data every 2 ms.
How it applies
- Engineering: The controller's configuration lists every PROFINET IO device with its device name, GSDML file, modules and update time. The controller builds the connections from this configuration; devices that aren't configured don't exchange I/O data with it.
- Commissioning: At startup the controller finds each device by its name, assigns the IP address and parameterizes the modules. A device with a wrong or missing name stays unreachable, which is one of the most frequent commissioning faults.
- Diagnostics: The controller receives alarms and diagnostic data from its devices and signals failed connections, for example when a device misses its watchdog time.
- Documentation: The documentation team documents which controller owns which devices, the configured update times, the device name scheme and how the controller reports a failed device to the operator.
IO controller vs. IO device
The IO controller holds the configuration and drives the cyclic exchange; an IO device provides the process data of its modules. A controller serves many devices, while each submodule of a device belongs to one controller; the shared device function lets several controllers use different submodules of the same device, and system redundancy pairs two controllers. PROFINET also knows the IO supervisor, an engineering or diagnostics station with temporary access.