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caffreys_col
#1 Posted : Friday, October 07, 2011 10:34:16 AM
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Joined: 4/6/2011
Posts: 40
Location: Grimsby UK
Hi All,

I have been asked to develop a way of returning the start and end time (and therefore duration) of an event, in Excel. Anyone know how to do this??

Example;
A PI value has a range of 0-100. I need to know the start and end time of any periods where the value went above 60 for more than 3 minutes over the course of a day. I've tried filtered calculated data, advanced filtered data, but can't find a way to combine everything I want into one Datalink call.

My current idea is to find the first time the value goes above 60 (using the findge function), then use the time returned as the start point for finding when the value drops below 60. I'd then repeat this for the rest of the day. However I can't get Datalink to return a timestamp, it says the data type is incorrect. Anybody got any ideas how to get round this??

Thanks
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squatty
#2 Posted : Monday, October 10, 2011 8:18:04 AM
Rank: Advanced Member

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Joined: 4/7/2011
Posts: 137
Location: KZN, South Africa
I used sinusoid as an example. The first part of this filter expression will filter results when sinusoid is above 20, or the UP leg as I call it
TagVal('sinusoid')>20 and PrevVal('sinusoid')<20

The second part will filter result when sinusoid goes below 20, DOWN leg.
TagVal('sinusoid')<20 and PrevVal('sinusoid')>20

Now you combine these two filters and use compressed data with this filter.
TagVal('sinusoid')>20 and PrevVal('sinusoid')<20 or TagVal('sinusoid')<20 and PrevVal('sinusoid')>20

Give this a try and let us know. I'm sure there are much better ways to calculate this using PI-ACE.
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