Client prioritization
To define an access sequence for the clients, the TwinCAT 3 HMI server offers the option of setting a prioritization. This ensures that the connection to a low-order client is closed and the high-order client can log in. The configuration takes place in the settings of the TwinCAT 3 HMI server. The local client always has priority. If two clients from the priority list are affected, the order of the entries is checked.
- 1. Open TcHmiSvr.
- 2. Select the Web server tab.
- 3. Select the Client priority list entry
- 4. Click on Add
- The following dialog opens.
- 5. Enter the IP address of the preferred client.
- The registered IP addresses are entered one below the other in a list.
Example:

A total of four client licenses are required (TF2000 + TF2020) so that all four clients can access the server at the same time. If you only have three licenses available, for example, this means that a client cannot establish a connection to the server. To ensure that certain clients can always establish a connection, they must be entered in the client priority list. According to this figure and the previous priority list, Client 3 can log in if a free license is available. If the other three clients log in, they would kick Client 3 out of its session.
Error message on the logged off client:

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