I have a backend gateway with an alarm journal set to send alarm events to a database. I have another gateway connected over a remote gateway and I want this gateway to be able to access the alarm journal on the first gateway to show historical alarm events from the database.
Whats the best way to do this? I remember a setting related to alarms where you can enable it to query only…etc…where it that located?
If gateway A is the one with actual DB access and the primary journal, then on gateway B you would set up a ‘Remote Alarm Journal’ profile type. If Gateway A allows it, then you’ll be able to query (and optionally store) alarm journal events on gateway B.
So I have a backend gateway which houses the tags and therefore has the alarm history tied to it. Its using a database called DB. The frontend which houses the perspective graphics, etc, also has access to the DB. I am thinking I need the alarm journal profile on the backend so the alarm history can store the alarm events from the backend housing the tag provider to the database. I have an alarm journal object on the frontend and I do have the same DB access to it. I thought about doing a remote alarm journal but that would be writing alarm events to the backend which isn’t what I need. I just need the frontend alarm journal object to be able to access the alarm history and alarm events from the backend alarm journal connection. How would I set this up?
Or would another way be to set up the alarm journal profile on the frontend housing the graphics. Then have the backend, which has a direct connection to tags, have a remote alarm journal type so it will be then send the alarm events from the backend to the frontend. And since the frontend has the graphics and the alarm journal profile on it it should then be able to access that alarm journal profile directly?
Have it working as follows:
Set up alarm journal profile on frontend which does have connection to DB.
Alarm Journal object is linked to this frontend alarm journal profile.
Backend has remote alarm journal profile which writes from backend to frontend.
It seems to be working although is there another way to do this? Could I have still had the backend contain the alarm journal profile and have the frontend somehow access it?
I would do it the opposite way; if the backend has the tags, it should be ‘in charge’ of the alarm journal.
A remote alarm journal can be restricted to just querying via service security - if you put the actual DB access on the backend gateway, you can also restrict the alarm journal access to ensure that the frontend isn’t actually writing anything to the tag.
As much as possible, I’d recommend not tying your frontend gateway into your actual DBs and tag providers - that both increases risk (of inadvertent access/data changes as well as increased load on your DB) and maintenance surface. An advantage of the ‘frontend gateway’ concept is that, at least in theory, you’re decoupling the load - and if your existing frontend gateway starts to be overtaxed, you can stand up an additional ‘frontend’ gateway pretty easily. The more ties the frontend has to the backend, the harder it is to duplicate.
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