Hello, it has come to my attention that when an alarm occurs multiple database entries are saved for the duration of the alarm's active state. This creates so many database entries that the database fills up and crashes after a short period of time (~2-4 weeks, not sure exactly).
There is a feature in Ignition where when an alarm occurs more than a specified number of times (6 is default), then the alarm is automatically turned off. Why would this feature be implemented and have another feature which fills up a database if an alarm is going on for a month? For startup and commissioning time periods, this is a fairly likely scenario. If you use the same database for other systems, then it can risk that data as well.
Does anyone know about a multitude of database entries for the same alarm filling up a database?
What database are you using? If you're using MS SQL Express, it has a limited database size and isn't recommended for use due to that size restriction. If you're using SQLite, while it may work, it's not good for long term storage either as it's file based rather than a true database server. I haven't encountered this issue except on SQL Express where the historian was recording data and eventually filled up the database and hit the size limit. I haven't had the issue with alarms, so haven't checked them to see how often they log, but unless you have alarms flapping on/off a LOT then it shouldn't be logging data (I wouldn't think) while an alarm is just active and not flapping.
Thanks for the response. It is a real MSSQL database, enterprise. So perhaps they sized it too small. In terms of the alarm flapping on/off, I think you are correct in that it would eventually fill up any database if it went on long enough. I wanted to make sure Ignition wasn't creating a new entry every second or something like that while it was continuously active, as I have not found any settings to this effect.
This was observed by a colleague so I don't have the exact numbers or whether the alarm was continuously on, or flipping quickly. It was conveyed to me that it was just constant. Perhaps this thread should be resolved as I cannot provide specifics.
I'm programming a system right now in our office and have hundreds of alarms due to the fact that I only have a PLC with no I/O and they've been on for days/weeks straight, and my alarms database is only 15MB.