Shared Device

The ProfiNET feature "Shared Device" is supported by the EL6631-0010, by the TwinCAT Supplement from version TC211 22.xx (= TC2 R3).
Shared Device features a function that allows two controllers to simultaneously access one device and, if applicable, the same process data image.

The difference to the use of the virtual device lies in the fact that, when creating a virtual device, a completely new device is generated (with its own name, MAC, IP, etc.). i.e. as a result the controller sees two separate devices and can establish two completely separate connections.

In the case of Shared Device, conversely, there is only ever one device. On the device side nothing needs to be engineered for this; the complete functionality is handled in the ProfiNET stack. A common example for this would be the use of the safety functionality. A "normal CONTROLLER" is assigned the "normal" inputs and outputs, while the F-CPU is assigned the safe I/Os. If the requested process image should overlap in both controllers, then the first AR (primary) that is established is given full read and write access to the submodule. The second AR (secondary) receives a corresponding ModuleDiff block at the submodules that are already occupied. If the primary AR is released, then the secondary AR receives an alarm now indicating that the requested submodule is free. The second controller now has the possibility, if it supports this, to re-parameterize the submodules and to adopt them into its AR.