In this blog we will explore simulating a Siemens WinCC Unified Version 19 HMI program using data from a connected physical PLC. In TIA version 19, the Siemens Communication Settings tool or Set PG/PC Interface is the easiest way to configure the online access path for the PC simulation to communicate with your hardware.
The Simatic Step 7 manager uses the S7ONLINE access point for communication on the PC/PG interface. By default, the access path on S7ONLINE is set to none as simulating a WinCC HMI program will run disconnected of the PLC program through Simatic manager. The HMI in this state will not display tags read from the PLC but will use HMI local tags and should be fully navigable.
Connection Parameters

The easiest tool to use for establishing a simulator connection is the Siemens Communication Settings tool located in the control panel. Opening the tool will provide you with all possible connection modules on the computer as well as their respective parameters and diagnostics tools. From the address menu you can configure your IP address in the network connections menu of your PC.
To establish simulator-hardware connection, open the Access points menu. Select S7ONLINE and open the dropdown arrow. From here you can select the interface parameter which should match the same pathway that the PC uses to communicate with the hardware. The module property should auto populate and match the network connection name you configured.

In older versions of TIA Portal there is an interface configuration tool found in the Windows control panel named Set PG/PC Interface. From here, you can set the same pathway that will enable communication between the simulator and PLC.
After opening the tool, navigate to the Access path tab and select S7ONLINE as the access point. In the box below you will see all available interfaces for the path to take. Select the module in the list that matches the communication method you are using to talk to your hardware.

After selecting the correct module, you can close the tool and launch your WinCC simulation from Simatic Manager or TIA Portal. Provided that you are in contact, the S7ONLINE point should update your simulation with real data coming from the PLC.
Troubleshooting
If the Set PC/PG tool opens but does not display the S7ONLINE access point, it may be resolved by downloading a Siemens PC_Identifier hotfix support package linked below.
SIMATIC S7-PLCSIM Advanced V4.0
Troubleshooting the PLC connection can follow the same path as a typical process to go online with hardware. Ensure that you have a stable ethernet connection to the PLC you are attempting to communicate with. On the S7ONLINE path that you configured, note the module name that auto populated when the interface parameter was assigned. In your Windows taskbar search "view network connections." Then, in this menu locate the ethernet driver that has the same module name as on the S7ONLINE path you are trying to use. In the popup window, go to properties then IPv4 and assign your own IP address on the same subnet and mask as the desired PLC. Once complete you should be able to ping the IP of your PLC from the command prompt.
If the simulated instance of your HMI still does not communicate with the PLC, stop the simulation and verify that the PC/PG interface selected when trying to go online with the PLC is the same as configured in either of the tools. Redownloading the program and verifying run mode is active may also assist with troubleshooting measures.
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