Introduction
One of the cool features of PROFINET is the shared device. Not a lot of people know about it but anyone who happens to have an issue that the shared device can help, it can easily become a game changer.
So what is a shared device in PROFINET and how to use it? Let’s find out together.
What is the Shared Device
In short, an PROFINET IO device whose modules are used by different PROFINET IO controllers is a shared device.
The shared device functionality is supported by a wide range of PROFINET IO devices. It is possible to share ET200SP input modules as well as S120 axis between different PROFINET IO controllers.
Benefit of the Shared Device
In any big project, there will be multiple PROFINET IO controllers. Potentially some IO devices can sit in a particular location / environment that limits the possibility of adding additional IO devices nearby and more than one IO controller needs the sensor signals from it.
Without the shared device, one IO controller must relay the signals to another IO controller which requires additional programming.
With the shared device, the IO controllers can communicate with the IO device at the same time and get the IO data themselves.
Shared Device Configuration Demonstration
In this demonstration, two IO controllers (PLCs) share the same ET200SP station. The below demonstration will show how to configure the two PLCs’ projects.
Multi Assign The IO Device
To share the IO device, it must be multi-assigned to the both IO controllers. Follow the below steps to multi-assign the ET200SP.
Now the IO device has been multi-assigned to the IO controllers.
Assign Each IO Modules
Since the IO device has been assigned to both the IO controllers, the IO device’s IO modules can be assigned to either IO controller separately.
As shown below, in the ET200SP’s interface module’s configuration there is a shared device option. Inside this option, we can assign each ET200SP IO card to different IO controllers.
Shared Device Configured in Different PLC projects
The above example demonstrates how to configure the shared device in the same PLC project. However, in many cases the IO controllers may have their own PLC projects hence the shared device must be configured in different PLC Projects.
To do so, simply configure the same IO device in the different PLC projects then carry out the below configurations.
Specify how many IO controllers from outside of the PLC project will access the IO device.
Specify the IO modules that will be accessed from the outside of the PLC project.
Afterwards, download the hardware configuration to both the IO controllers and they should be able to share the IO device.
Conclusion
Shared device is a PROFINET feature that is widely supported. It can be particularly useful when adding additional PROFINET IO devices is difficult and it saves the effort to relay the IO devices’ signals from one IO controller to another.