Trending machine status from a trafic light tower

Hi Jan Lonij ,

I'm curious if others in the community have a novel approach to solve this problem?

So when you untick "Instant Trend" what happens? I would assume this gets data from the Trend Tag (also assume you have a Trend tag defined?). Is it not displaying in the correct format? While the Instant Trend does display with correct format, just no history?

With regards to Active Alarm or Summary/SOE page, that is very easy to solve. Assign the alarms you have defined for this purpose to a unique alarm category like "AlmEvents" and within the definition of this alarm category, set "Show on Active" and "Show on Summary" to FALSE. This wll ensure these events don't appear on your active alarm page or Summary/SOE page.

Let us know how you go.

Kind regards

Olivier

It sounds like you just need to define a trend tag with the same variable name, then uncheck the Instant Trend checkbox in Process Analyst. When you add a tag to the chart, choose Trends instead of Variable Tags and it won't use Instant Trend mode.

If you display a Variable tag in PA, no history exists so it will just display the live value of the tag and will cache the values in memory while the pen is displayed. There will be no history from before the tag was added to the display. That's what an Instant Trend is. It's mainly for troubleshooting a problem and creating a live chart for a variable tag that isn't being trended.

Using the alarm tag as Olivier mentioned is a good option if you don't want to add trend tags. 

The cool thing about the Instant Trend feature (which gets data from Variable Tag directly) is it can be higher resolution, e.g. display more data points and not be limited by the Trend Sample period. But it may not be suitable in all use cases. Typically you would just use a Trend Tag.

Hi Oliver,

Setting "Show on Active" and "Show on Summary" to FALSE did the trick for me.
Now |I have a clean alarm page, without these 'alarms' visable.

Thanks for your help.

Is there a way to display the percentage [%] of GREEN based on the selected timespan so you can indicate, lets call it, productive time%

Hi Jan,

I think the answer is "no" on this.

You can certainly implement a custom column in the Process Analyst. The example project demonstrates one of these with the "Difference Cursor".
Implementing a Custom Column

But where you are are going to run into problems is being able to get the data again for the selected timespan from the alarm server which I think will not be possible from our current API's. Unfortunately there is no API to get the data that the Process Analyst has already captured - which would be the most optimum path.

If you trend the "Green" tag as an analog trend (span to 0-1) and display the average value , the average will equate to the % (i.e. 0.2 = 20%)

Thanks for that tip about displaying as an analog trend to get the average value. 

I have a similar situation, with traffic lights that we typically display as a digital trend (just logged as a standard trend tag).  For most purposes, displaying as digital is the more useful format for the operators, but I was always slightly frustrated that the "Average" didn't work in that mode.  Nice to know it is possible using analog mode for the same tags. 

Below is an image from the site, using the same tags in both formats to demonstrate what Tony has said.