Hello,

To monitor the Profinet network of slave devices in the S7-300 with a 319-3 PN/DP CPU using TIA Portal V16, you can follow these steps:

1. Open your project in TIA Portal V16 and go to the "Device Configuration" tab.

2. Expand the CPU node in the device tree and double-click on the "PROFINET interface" to open its properties.

3. In the properties window, go to the "Diagnostics" tab and check the box for "Enable diagnostics".

4. Select the "Inputs" tab and check the box for "PN diagnostics".

5. Click on "Apply" and "OK" to save the changes.

6. Go to the "Online" tab and connect to your CPU.

7. In the "Devices and Networks" view, expand the "Profinet interface" node and you should see a list of connected devices.

8. Double-click on a device to view its properties, including its status and diagnostic information.

9. To send this information to an HMI, you can create a Profinet data block in your program and use it to read the diagnostic data from the CPU. Then you can use this data in your HMI application to display the status of the connected devices.

Note that the exact steps may vary depending on your specific configuration and the version of TIA Portal you are using. However, the general approach should be similar to the steps outlined above.

Regards

Scott