SCADA with several workplaces (k)

0220_multiple_pc_en
Two workplaces over a technology

This is the situation where there are two workstations in the system, a main PC with SCADA, and a secondary PC with the same or different functionality and access rights. The licence for the secondary workstation (which shares the database with the main workstation so that both workstations have access to the same technology) is cheaper than the main licence – see the pricelist. There are two main topologies:

    • the secondary workstation connects to the process stations directly (the process stations accept connections from both the main and the secondary workstations at the same time). The secondary workstation is operating even if the main workstation is down. The disadvantage may be that the 3rd party systems directly integrated into the main management station, such as M-Bus meters over RS232, are not available at both stations. This may be fixed by using SoftPLC Runtime as in Configuration h above.
    • the secondary workstation connects to the database of online values   - here, all 3rd party systems are integrated into the main workstation, which has to operate 24/7, and which acts as a communication server for the secondary workstation(s). All systems integrated into the main workstation are available at the secondary workstations. This topology is getting obsolete with the increasing number of SoftPLC Runtime 3rd party drivers, and the above mentioned configuration (h with SoftPLC Runtime) is the preferrable one.

The secondary workstation may be also connected over the Internet. A single TCP port has to be opened only. The connection is protected by username and password, however, stronger measures may be taken, as VPN for example.