alarm and event notification DSC

[Maryam]

I can't understand the functionality of these DSC VIs:

Acknowledge Alarms .vi

Set user Defined Alarms .vi

Request Alarm & Event Notifications .vi

I appreciate any guide.

[EmmaR]

Hi Maryam,

Have you tried using the context help?

LabVIEW has a built in dictonary of functions - if you go to "Help" on the main labVIEW toolbar and select "Show Context Help" from the drop down list a contect hlpe window will open.

If you then use your cursor to hover over the VI you want information about, the context help window will populate with information about that VI.

There is also usually a link "Click here for more help" that appears which if you click it will pull up a more extensive help file which includes information on the terminals, accepted data types etc of the VI.

You can also use the Example finder to get example code which uses the VIs these example come with a full description and instructions on how to use the code, block diagram and front panels are also annotated with the steps of execution.

To access this library of examples click on "Help" on LabVIEWs main toolbar, select "Find Examples.." from the drop down list. The "NI Example Finder" should then open.

You can then either browse to the appropriate functionality pieces of example code by expanding the tree structure uber the "Browse" tab. Or Use the "Search" tab to pull up example code linked to a key word.

If you enter "acknowledge" as the keyword and do a search the example finder provides the example "View and Acknowledge Alarms Remotely" which you may find useful.

To then load the example VI simpley double click on the VI title.

I hope that this informaton helps you.

Regards

Emma Rogulska

NIUK & Ireland

[Maryam]

What you said was very basic, by the way thanks Emma. there's no example showing the usage of these VIs, I can't understand for example in "Acknowledge Alarms.vi" what's the goal of this function?!We just enter some information in string format and just this? Where is this usefull? I don't get this.

[EmmaR]

Hi Maryam,

Acknowledge is where the sequence action that indicates recognition of a new alarm.
Where an alarm is an abnormal process condition. In the LabVIEW Datalogging and Supervisory Control (DSC) Module, an alarm occurs if a shared variable value goes out of its defined alarm limits or if a shared variable has bad status.

This is the URL of the DSC module Glossary:

http://zone.ni.com/reference/en-XX/help/370246D-01/lvdschelp/dsc_glossary/

If you want to know more about the general functionality of alarms and events and what to use specific VIs for.

The fisrst call as I said previously should be the context help, check the example library and the NI developer zone. Another reasource which you can check is the DCS module "VI, Function, & How-To Help".

Click on the "Help" then "VI, Function, & How-To Help", expand the following items in the tree structure "DSC Module"> "DSC Module VIs & Functions" > "Alarm & Events VIs".

For future reference it would be helpful in future if you gave more information in your posts eg what version of LabVIEW you are using - so can post back relevent versioned example code.

And what you are trying to do - why are you interested in the DSC alarm VIs, could make more specific replies given this information.

Sorry if my initial replies are basic but I had no way of knowing the level of information you were looking for and you did not say what you had already tried/ looked up.

Alarms can be used in many applications but as I said their basic functionality is to alert the user to an abnormal process condition eg sub/super limit values or bad status.

I hope the above helps but if you require more information please let me know what it is you specifically want to know.

Regards,

Emma Rogulska

NIUK & Ireland

[REM1]

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@Maryam wrote:
What you said was very basic, by the way thanks Emma. there's no example showing the usage of these VIs, I can't understand for example in "Acknowledge Alarms.vi" what's the goal of this function?!We just enter some information in string format and just this? Where is this usefull? I don't get this.

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Every alarm has a life-cycle, the alarm is initiated, acknowledged (noticed) and finally cleared.  No alarm can be cleared until it has been acknowledged.  When configuring an alarm you can choose between "Auto Acknowledge" which has the data engine set the acknowledgement when the value returns to the normal band or "User Must Acknowledge" which requires someone external to the data engine to enter acknowledgement information.  In the event that an alarm is configured as "User Must Acknowledge" the alarm will stay active even if the value returns to the normal band until the alarm is acknowledged.  Generally this is used for very serious conditions when you want to ensure the user is alerted even if the value was outside the normal band even for a very short period of time.

[Maryam]

Thanks, this really make sense to me.