Analog Alarm Deadbands

Hello there,
I'm wondering if anyone has a bit of a typical rule for creating deadbands on analog alarms. I work with a Bailey Infi-90 system, and
when you alarm an analog point, there is a deadband setting that can be made globally for all points in a certain section (called a segment). I'm thinking 2 - 4%, but I was wondering if anyone has experience with this, and has some typical settings or best practices they use. The setting is in % of span.
Thanks.
Curtis Keyes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
A few % is fairly typical. Not worth spending too much time on in terms of determining generic rules. Find out your persistent alarms and address them using whatever works.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

dead bands are application sensitive. If the process is defined well and there is little chance of any small variations then a small percent is just as good as a large one. If the process has a lot of hic-ups that do not result in a condition that needs to be investigated then larger percent dead band could be used.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
One method is to evaluate the short term standard deviation of the process. Setting the deadband at two standard deviations will usually prevent realarming due to noise.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.