Example of a hot backup pair

This section describes a typical working scenario to set up an alarm backup pair. The figure below shows the configuration of a hot backup pair for an InTouch tank farm application. In this example, the InTouch application monitors pump pressure as an alarm condition.

All three computers are running the InTouch HMI. The hot backup pair includes FrmPN as the primary provider and FrmBU as the backup. These two nodes serve as alarm providers within an InTouch Distributed Alarm system.

The Hot Backup Manager run on the FrmAp node. The InTouch client application runs on FrmAp and consumes alarms from the two providers of the hot backup pair.

The InTouch application running on FrmPN generates two summary alarms for pump inlet and outlet pressure. The two alarms belong to the TnkFrm1 alarm group. The InTouch application running on FrmBU generates two logically equivalent alarms for pump pressure.

When you set up a redundant hot backup pair, you:

• Create a hot backup pair.

• Set the alarm record key fields.

• Create an alarm record mapping file.

• Import the alarm record mapping file.

Create a hot backup pair

1. Open the InTouch application in WindowMaker. In this example, the application runs on the FrmAp node.

2. Open the Alarm Hot Backup Manager. Do the following:

   1. In the Tools view, expand Applications.

   2. Double-click Alarm Hot Backup Manager.

3. Select New Pair. The Add New Pair dialog box appears.

4. Complete the options of the Add New Pair dialog box, as shown in the following figure.

   

5. Select OK to return to the Alarm Hot Backup Manager dialog box.

6. Keep the Alarm Hot Backup Manager dialog box open within WindowMaker.

You are done with the first step to create a hot backup pair. Next, complete the following procedure to generate a unique mapping key to the paired alarm records stored in each provider’s alarm repository.

Map alarm record key fields

7. Select the hot backup pair in the list.

8. Select Set Key Fields. The Select Key Fields dialog box appears.

   Complete the options of the Select Key Fields dialog box, as shown in the following figure. The alarms between the primary and backup provider are logically consistent but have been assigned different names and belong to different alarm groups. A unique mapping key to records stored in each provider’s alarm repository can be generated by selecting Alarm Group, Alarm Name, Alarm Class, and Alarm Type as Design-Time options.

   

9. Select OK. When a message appears, select Yes.

You are done with the second step to create an alarm record mapping key.

In this scenario all three nodes are running InTouch applications. The two provider nodes generate equivalent alarms, but are using different tagnames. The primary provider generates two summary alarms when a pump’s inlet and outlet pressures are too high. The backup provider generates two logically identical alarms for the same pump pressure alarm conditions. Next, complete the following procedure to create a mapping file that associates equivalent records stored in each provider’s alarm repository.

Create an alarm mapping file

10. Create a .csv file with Excel or a text editor like Notepad.

11. Enter the names of the file headers in the same order as the alarm record field options of the Select Key Fields dialog box.

    In this example, the file headers should be ordered by alarm group, alarm name, the class of alarm, and the type of alarm condition.

12. Map the alarms between the two providers on each row of the file.

13. The example of the Excel file below shows how the headers and alarm conditions should be specified for the two providers of the hot backup pair. Save the mapping file to a location accessible to the Hot Backup Manager running on the client node.

    

You are done with the third step to create an alarm record mapping file.

In the last step, you import the contents of the alarm mapping file to the Hot Backup Manager. In this example, the client application knows which pump pressure alarm records to acknowledge between the two alarm providers.

Import an alarm record mapping .csv file

14. Open the Alarm Hot Backup Manager.

    The alarm backup pair you created earlier should be listed.

15. Select Map Alarms. The Map Alarm Records dialog box appears.

16. Select Import. The Open dialog box appears.

17. Highlight your mapping file and select Open. The Map Alarm Records dialog box lists the alarm mapping records from the file.

    

18. Select OK. The Hot Backup Manager begins importing records from the file.

19. Select OK after all mapping records have been imported.

You can now run the hot backup application.