SERVER-CLIENT AND STANDALONE HMI DEVICES TROUBLE

SERVER-CLIENT AND STANDALONE HMI DEVICES TROUBLE

We are planning to implement a SCADA system for a factory process and would like your guidance regarding the correct architecture and configuration. 

My main question= HMI PCs with a limited tag license- how can they be operated in standalone mode? 

System Requirements

The system will operate in a Server–Client architecture under normal conditions.

  • During normal operation, the Servers will read data from the field devices.
  • In case both Servers fail, all Client and HMI PCs must automatically switch to standalone mode and read data directly from the field devices.

System Structure

1) Servers (Hot-Standby Redundancy)

  • 2 Servers: SERVER1 and SERVER2
  • Operating in hot redundancy mode
  • Unlimited tag license

2) Operator SCADA Stations (Client PCs)

  • 5 Client PCs: OS1, OS2, OS3, OS4, OS5
  • Each should be able to access up to 8000 tags
  • Unlimited tag license
  • Client PCs have Access to plc and other devices.

3) HMI Client SCADA PCs

  • 7 HMI PCs: DG1, DG2, DG3, DG4, DG5, DG6, DG7
  • Each will access up to 1000 tags
  • Each HMI has a 1500 tag license
  • HMI Clients have Access to plc and other devices.

My main questionHMI PCs with a limited tag license- how can they be operated in standalone mode?