The WIN-911 Dispatcher can be placed in Standby mode so that it tracks alarms but does not perform the notification. It can also be Activated to return to normal operation. A hot backup is a pair of WIN-911 systems where one system is ordinarily kept in Standby mode and is Activated upon server fail over.

To set up:

1. Install and license two copies of the software.

2. Configure the primary system.

3. Place the secondary system in Standby.

4. Duplicate the primary configuration onto the secondary following the SQL "Move to a different computer" instructions on this link: https://win911na.blob.core.windows.net/files/Products/WIN-911/3.17.5/WIN-911_SQL_Server_Redirect.pdf 

5. Move a copy of Activate.exe onto the secondary SCADA or whatever server controls failover.

Activate.exe - The Activate applet restores WIN-911 from Standby mode. This enables all WIN-911 notifiers.

Standby.exe - The Standby applet acts in a global manner to disable all WIN-911 monitored data points from triggering notification. The Log Viewer will still see the alarms.

6. Edit the Activate.exe config URL host to point to the secondary WIN-911.

7. Call Activate.exe upon failover (typically through scripting).

You can edit it in Notepad, I use Notepad++ as it has some formatting capabilities. When you edit the script you will find some instructions on how to implement the script. (NOTE: WIN-911 is not liable for this script)

https://win911na.blob.core.windows.net:443/files/Support/Downloads/Patches/WIN911_Failover.zip


Now that it's up and running, it's important to keep the two WIN-911 configurations the same; the easiest way to do this is open two browser tabs and make the same edits twice, once on the primary and once on the secondary. If things get out of sync, you can run the SQL move instructions again.

Detecting failure of WIN-911 to trigger fail-over is most easily accomplished by performing an HTTP request against one or more module information svc URLs. So, you can imagine a script running on the secondary SCADA server that periodically checks for the accessibility of the primary Dispatcher and calls Activate.exe upon failure. Of course the exact fail-over trigger is going to be application specific. If the SCADA has a fail-over mode, then that's probably the main trigger for calling Activate on WIN-911.


Example:


Since WIN-911 is used with many different SCADA/HMI packages, the system designer is responsible for writing a script or macro to automate the execution of Standby and Activate. Below is a generic concept of how this could be achieved.

The idea here is to have one WIN-911 system in Active mode and one WIN-911 system in Standby mode. If at any time both WIN-911s are Active, double the notifications will be made for monitored alarms. If at any time both WIN-911's are in Standby, notifications will be completely lost for monitored alarms.

This script would need to be run on both WIN-911 systems:


If ActiveNode = 1

Run C:\Program Files (x86)\WIN-911 Software\WIN-911 Enterprise\Standby Activate\Activate.exe.

Else

Run C:\Program Files (x86)\WIN-911 Software\WIN-911 Enterprise\Standby Activate\Standby.exe.

Where ActiveNode is some flag that changes when a failover occurs from your primary to secondary SCADA/HMI system.