Unable to select last Active Alarm

[Subho]

I am trying to select the last active alarm using following script.

void Screen2_Opened(System.Object sender, System.EventArgs e)
{
SQLiteConnection db = new SQLiteConnection("DataSource=Database.db");
string query ="Select [Text] from AlarmServer WHERE State = 'Active' ORDER BY ActiveTime DESC LIMIT 1";
SQLiteCommand comm = new SQLiteCommand(query);
comm.Connection = db;
db.Open();
SQLiteDataReader read = (null);
read = comm.ExecuteReader();
while (read.Read())
{
Globals.Tags.AlarmString.Value = (read["Text"].ToString());
}
read.Close();
db.Close();
}

But it always select Last-1 alarm and show its text in AlarmString tag. Where am I doing wrong?

I have also attached the project for reference.

[Russ C.]

It looks like the database write is too slow for the read.

You could do it this way in a script module:

Code: Select all

void ScriptModule1_Created(System.Object sender, System.EventArgs e)
		{
			Globals.AlarmServer.AlarmActive += AlarmStatus;
		}

		void AlarmStatus(System.Object sender, System.EventArgs e)
		{
			try
			{
				IAlarmEvent alarm = (IAlarmEvent)sender;
            
				Globals.Tags.AlarmString.Value = "";
				Globals.Tags.AlarmString.SetString(alarm.DisplayText);

			}
			catch (Exception) { }
		}

What this does is capture the triggering alarm event and pull its data, so only the most recent active alarm will be distplayed.

And remove the script from your Screen2

[Subho]

Thank you Russ for the script. It solved the problem.

I am also wondering if Alarm ID can be selected using the same script and acknowledge that particular Alarm when the "Close" button is pressed.

[nxen]

Hi Russ,

is there a way to clear the string when no alarm is active?

Thanks in advance.