Switch limit active/inactive in Realtime

[maryanp]

Hello.

I want switch off some limits in runtime. For example, when some equipment stoped for weekend. As I understand, I can use "AlarmGroups", but I can't change group of limit in runtime. Can I change limit property "Active" for activate every limit directly?

Thanks.

[markclemens]

Hi maryanp,

The active property of a limit currently cannot be modified in the runtime. You can however disable alarming for one or more variables, by setting the "revision" statusbit.

When the revision statusbit for a variable is active, the limits are still active, but no alarms will be generated.

You can set the revision Statusbit, e.g. using report generator, Recipegroup Manager, command input or via the programming interface in the runtime.

Best regards,
Mark

[maryanp]

Thanks Mark.

It good solving the problem for project, but my code not work correctly. What's wrong?

Public Sub ChangeLimitStatus()
    For i = 1 To 2
        Status = thisProject.Variables.Item("limitstatus[" & i & "]").Value
        Tagname = thisProject.Variables.Item("limitstatus[" & i & "]").Tagname
        If Status = 0 Then
                thisProject.Variables.Item("" & Tagname).StatusString = "REV = 1"
        ElseIf Status = 1 Then
                thisProject.Variables.Item("" & Tagname).StatusString = "REV = 0"
        End If
        MsgBox (thisProject.Variables.Item("" & Tagname).StatusString)
    Next i
End Sub

[markclemens]

Hi maryanp,

Perhaps this thread is helpful.

Best regards,
Mark

[maryanp]

Thanks Mark.

I can change status bit REVISION, but alarm messages MessageControl still sending. Can I change this as simple as possible?

[louis.paglaiccetti]

Hi maryanp,

As markclemens mentioned, by setting the revision bit to 1, only the alarms for the variable(s) are suppressed. But the other limit properties (limit color, limit text, limit function) are still executed. And usually the message control sends a message by linking a function to the limit, which is still evaluated.

Here is a short overview of "Suppression" capabilities in zenon generally. However, depending on your exact zenon version in use, you may not have all message control suppression capabilities.

Individual variables
Individual variables can be suppressed from alarming, by utilizing a special status bit called “Revision”. This is one of the 64 status bits which are available for each zenon variable and is commonly used when equipment is down for maintenance or repairs. When revision is set to true for a variable, the variable itself will be suppressed only for alarming. The other limit properties like, colors, etc. are still analyzed, and zenon still gets value updates from the PLC/IED for that variable. Simply while revision is true, no alarms are created.

Alarm Suppression for Alarm Groups or Classes
You can activate or deactivate alarming for an entire Alarm Group or Alarm Class. If you created alarm classes for each substation for example, you can de-activate all alarms for that specific class with a pre-defined zenon function.

Message Control Suppression
When you are using the zenon Message Control, you would normally create a special “Message Control” screen type in your project. This has pre-defined functionality to show a queue of messages sent and messages which failed to send from zenon. When you create this screen, and use the template it already offers the message control suppression dialogs, lists, and controls. This allows you to stop only the messaging for either an Alarm Group, Alarm Class, Alarm Area, or for Equipment Groups. The alarms will still be created and logged by zenon, but if using this method, zenon will just not send the message for the Groups, Classes, Areas, or Equipment which you define.