Redundant SCADA system

[tashinz]

the customer wants two SCADA operate as master and slave where slave jumps into operation only when master is down. I think the customer saw that in iFIX and therefore he put that feature in project. Now, I saw in CX-Supervisor release 1.3 Manual page 239 in Redundant server section how you can configure multiple CX-Supervisor SCADA servers that all do the same thing and clients collects data from the one server and can be switched to another in case of server failure. OK, but this is not redundancy since all SCADA servers are working. we need one that works (master) and another that sleeps (slave) until master is down. Does anyone have more information on this? any help? Edited December 27, 2006 by tashinz

[Berti Baker]

Yes I've heard for larger SCADA with multiple stations and redundant stations iFix is easier (therefore more suitable) than CX-Supervisor. I read the User Manual chapter which does describe some basic topography concepts including redundant server although I haven't seen any specific features for this. I imagine you could have 2 CX-Supervisors acting as servers (or use OPC Servers) with the client machines programmed to detect a failure and switch to the other machine (e.g. by calling 'EnableGroup()' for points defined for the other machine, or changing the PC Name on the CX-Supervisor ActiveX Communications Control etc). But my point is that you would need to develop your own failure detection system and switchover code to achieve this. Even then, remember that many systems are local to each client (e.g. Data Logging, Alarm History and acknowledgement, Error log) so still may not be what you are looking for. So it might be easier using iFix or other (any other suggestions?) but then Supervisor might be able to save you a sum *IF* you don't mind a bit of hard graft Bertie.

[tashinz]

Yes, I've assumed it could be done by writing my own code, but you're right, that is not what I need, system redundancy. so, no other way than use ifix? does the citect supports redundancy? thanx

[PdL]

Yes, Citect supports redundancy, I have done a double server redundant system. Attached article might be outdated but it explains the basics. Redundancy.pdf

[tashinz]

thanks PdL. what citect does regarding this article is exactly what I need. any other ideas? CX-Supervisor is not in the game then. thanks to all

[paulengr]

My SCADA/HMI layout is pretty simple. There are 5 servers. Server #1: SQL Server. Server #2: Web server. Supports both a higher end management interface and a sort of "backup" interface so that if a client node craps out, you can get to a web-based interface to get by. Also designated as an offline backup for servers 3 & 4. Server #3: SCADA/HMI server. Uses Cimplicity HMI. Server #4: Redundant backup to #3. Server #5: Offline SQL server backup (also used as a test bed for SQL stuff). Since the redundancy capabilities are built-in, all the clients will naturally switch over if for some reason the main server dies. The only thing that doesn't naturally migrate over is anything triggered off the SQL server which has no online backup right now. I have only had two or three incidents since this setup was installed where we had to exercise the redundancy features. In one incident, we lost a major network backbone link. I physically carried one of the servers to the other end of the plant to restore some service. In another couple incidents, for various reasons one of the servers crashed and didn't recover. Since we recently went to UPS's backed up by a natural gas generator though, these incidents have been totally eliminated.