Any possibility to define variable limits for alarms

[Helene]

Hi,

I need to define variable LO and HI limits for alarms. That is, these LO and HI limits should be linked to different tags.
In the tag configuration editor, we can only give constant values to the LO and HI limit fields. Is there a way to associate tags to these fields, instead of constant values?

[Philip McDermott]

Hi helene.

My implementation to this was to use the tag Attribute VI's and have a seperate program that checks that the current HI or LO value with that of a tag storing my HI set point and another Tag Storing my LO Set point. If there is a diffrence in value, the appropriate alarm level gets changed to match the current value.

How are you changing your values? I have a slider on the front panel that triggers and event on change to update the tag.

However a point you may or may not have noticed is that if you change the LO or HI value using the Tag Attribute VI's on one computer, this change is not carried across to others. You will have to programatically run the update program mentioned above continuously on every computer running the system
.

This is a very large mine field that you will have to take extra care of. Think about what would happen on startup of the various clients, will there be a point when your computers fall out of sink with each other? will the current alarm set points be reatined when the computer is shut down and restarted?

I sent a very long time coming up with some solutions for all these problems. Which way you chose to do this depends on:
Number of computers
Frequency of limits changes
Number of tags you wich to change
Whether you system is server client or multi server based.

Let me know If you want to know more.

Later

Phil McD