Server Requirements and Licensing

A minimum recommended configuration for a Thin Client Server is:

  • Installation of VTScada, licensed for thin client connections.
  • Access across a network.
  • The server name should contain only letters, numbers and hyphens (as defined in Section 3.5 of RFC 1034 and Section 2.1 of RFC 1123 of the Internet Engineering Task Force). Characters such as underscores are not recognized by this standard and may cause unexpected behavior.
  • In the event that the clients connect to the Thin Client Server via proxy servers (common where a firewall is used), it is advisable that the proxy servers support the HTTP 1.1 protocol, rather than only HTTP 1.0.

VTS/IS Clusters and Server Lists

A cluster is defined as the list of machines configured in the VTScada Internet Setup dialog, Server Setup tab, and therefore sharing the sum of those server's licenses for client connections. These must be computers running VTScada that can see each other via VTScada Remote Procedure Calls (RPC).

Licensing for VTScada Thin Client Servers

VTScada Thin Client Servers and the connections made to them are subject to the following licensing restrictions:

  • Whether the server is enabled.
    The server is enabled in VTScadaLight installations, with one allowed connection.
  • The number of concurrent VTScada Internet Connections you can make to a server.
    Depending on the licensing options you purchased with VTScada, you might have the privilege of connecting from zero to unlimited thin clients to your server.

Licenses are managed based on a cluster of configured servers.
For example, if one server in the cluster is licensed for 5 connections and another is licensed for 10, you will always have 15 available connections. If the 10-license server goes offline temporarily, your available license count will not drop to the remaining 5 but will remain at 15 on the server that is still running. No existing connections will be lost. For complete details, see: License Clusters later in this topic.

VTScadaLight licenses may have one Thin Client connection from the local network.
Remote computers must connect to the local network using a VPN.

 

You can find the number of licensed thin client connections for any server in the License Management dialog, available from the VTScada Application Manager (VAM).

The number of licenses in use is counted on the basis of concurrent sessions, regardless of whether these are from one computer or from many computers. Each connection to a VTScada Thin Client Server counts as one license in use. If, for example, you opened two tabs in Internet Explorer and connected to your VTScada Thin Client Server from each tab, then that would count as two licenses in use. Pop-up windows do not consume extra licenses.

An exception is that for support purposes, certain Trihedral-supplied debugging tools (such as the "Debugger", "Profiler", etc.) can always be accessed via the VTScada Thin Client, even if their use would exceed the license allocation.