Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 108464289, Entry date: 06/22/2018

What settings do you have to make when installing a multiple station system in SIMATIC WinCC Professional?

  • Entry
  • Associated product(s)
Several requirements must be fulfilled in the configuration of your Windows environment in order to enable multi-user operation of the SCADA system SIMATIC WinCC Professional.

If the settings required for this are not correct, there is no guarantee that operation in multi-user mode is error-free or whether it is at all possible.

Make the following settings on your computer to meet the requirements for multi-user operation:

1. Assign IP address

The IP addressing is the basis for a working logical network. Ensure that the computers to be networked are in a physical and a logical network.

In order to fulfill this condition, you must think about how to structure you network already when assigning the IP addresses. It is not possible for two computers from different logical networks or subnetworks to communicate if you are not using a router.

The network address and subnet mask define the association of a computer to a logical network.

Network address: it is not the IP address of a computer that is meant here, but the address of the network, in other words, just a part of the character string.
There are three different classes of network addresses:

Class Available networks Available hosts Range Example of a network address in the range Standard subnet mask
A 126 16777214 1-126
B 16348 65534 128-191
C 2097151 254 192-223
Table 1: Network addresses for TCP/IP

Note on subnet masks and IP addresses
Further information on this topic is available in Entry ID: 2073614.

The range of 127.X.Y.Z is reserved for loopback tests and interprocess communication and is not a reliable network address.

Example of a network address: 142.16.x.y | Network | Host |

This is an example of a Class B address. You can tell this from the address range which is from 128 to 191 for Class B. The first two tetrads correspond to the IP network address in this case.

In the case of different IP network addresses (142.16.x.y and 142.11.x.y, for example) you must make further preparations for the client-server operation, because you need a router (gateway) for different network addresses.
When using routers, follow the instructions in the manual "SIMATIC WinCC WinCC Engineering V15 - Options" 
(Entry ID: 109755217),  in the section entitled 5.5.2 "Access computers outside the subnetwork".


  • You can test correct computer addressing with the ping command.
    For this you open the input prompt (Start > Run > cmd) and execute the "ping +IP address" command (ping, for example) for each other computer. If you do not get a response, you must check the complete network configuration and parameterization.
  • All SIMATIC WinCC Professional stations must be logged on either in the same workgroup or in the same domain.

2. Configure name resolution
If you are not using a DHCP service in conjunction with DNS in your network which does this task automatically, you must configure the "lmhosts" file for name resolution. If you are using a DNS and WINS server, the system also does the name resolution.

The "lmhosts" file is in the following path in Windows: <Drive>\Windows\system32\drivers\etc\ Open the file with the text editor and enter all the computers that can be reached in the network according to the example in the file. Delete the comments above the entries and then save the changes in the file.

Make these changes on all the computers.

In order to continue optimizing the name resolution, write the keyword "#PRE" after each entry (default maximum of 100 entries). Entries with this code word are buffered in the cache right at system start. In the case of IP address resolution, the cache is read out first and then the "lmhosts" file if not all of the computer names can be resolved.

Fig. 01: The "lmhosts" file after configuration

In large networks, in addition to the "lmhosts" file you should also configure the "hosts" file from the same directory in order to accelerate name resolution.
A detailed description of the "lmhosts" file is available on the Microsoft web pages.

You can perform another ping command to test whether the changes have been applied. Open the input prompt (Start > Run... > cmd) and execute the "ping + computer name" command (for example, ping WINCCPC01) for all the computers that you entered in the "lmhosts" file in the previous step.

If you get a response and the computer name has been resolved in the associated IP address, the file is configured correctly and the name resolution works in the network.

3. Check operating system
Which version of SIMATIC WinCC Professional requires which operating system is given in Entry ID: 64847781.

Assignment of rights
To find out which user rights are required for specific actions you should refer to the manual "SIMATIC WinCC WinCC Engineering V15 - Options" 
(Entry ID: 109755217), in section "Defining users in Windows".

If you install an update (formerly hotfix) or a Service Pack for WinCC, you should always read the Release Notes for this extension. Under certain circumstances the required user rights might change.

4. Configure terminal bus
You must configure the terminal bus for the right network card in the SIMATIC shell. If you are using multiple network cards there is the danger that the network card over which the communication is supposed to run is not selected here. Please refer to
Entry ID: 88780011. The SIMATIC Shell (with Windows 7) is available under "Start > Computer > Other".

Fig. 02: SIMATIC Shell

Another indicator that the network is functioning (availability of the other computers) is that you can see the projects of the other computers in the network in the SIMATIC shell.

5. Check order of network cards
The order of network cards defines the order in which the network services access the network cards. You must therefore ensure that the network card/connection (that you have selected as terminal bus) is in first place.

If you are using Windows 7 or Windows Server 2008, you must make settings in the Explorer window to get to this setting. For this you switch to the Windows Explorer. Show the menu bar via "Organize > Layout > Menu bar". You can also have this menu bar displayed temporarily with the "Alt" key.

Fig. 03: Display of the menu bar in Windows 7 and Microsoft Server 2008

Depending on the version of Windows you get to this setting via:
"Control Panel > Network Connections > Advanced > Advanced Settings > Network Cards and Connections"
or "Start > Control Panel > Network and Sharing Center > Change Adapter Settings > Advanced > Advanced Settings... > Adapters and Connections".

6. Install firewall
Computers often have a firewall installed for security reasons. Only the Windows firewall is released for operation with WinCC. If you disable this, you must then run the SIMATIC Security Control ("Start > All Programs > Siemens Automation") and click "Repeat Settings". Port filters are generally likewise not released.
Concepts and guidelines on the topic are available via the "Security Notes" link.

Further Information

  • The manual "SIMATIC WinCC WinCC Engineering V15 - Options" (Entry ID: 109755217), section 5 "WinCC Server / WinCC Client", includes more information about multiple-station systems. 
  • Information about redundancy is available in the manual "SIMATIC WinCC WinCC Engineering V15 - Options" 
    (Entry ID: 109755217), chapter 3 "WinCC Redundancy".
  • More information about installing WinCC Runtime Professional (TIA Portal), SIMATIC Shell, network configuration, Windows user settings and about the SQL Server is available in Entry ID: 88780011.

Additional Keywords
Configuration of a distributed system, Client-Server, Coordinated operator stations

Security information
In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic, state-of-the-art IT security concept. Siemens’ products and solutions constitute one element of such a concept. For more information about cyber security, please visit