Is a ValueStream needed to plot historic values for a property?

[riaanmarx]

Hi Everyone,

I have only been introduced to TWx 2 days ago, so please excuse if this is a stupid question:

I have defined a GenericThing-based Thing called "MyThing" with Integer property "MyProperty".

If I want to plot a graph on a Mashup (using the line graph widget), of the property "MyProperty", as it changed over time, would I need to somehow map a ValueStream to this property? 

I have been trying to do this and I cannot figure out how to map the stream and property. I searched the tutorials and courses, but they don't show examples of this use-case.

Thank you in advance and kind regards,

Riaan

[PaiChung · Accepted solution]

You would need some sort of historical data store.

Value Stream or Stream is a structure that you can use.

It would be the easiest way for you to use a ValueStream and set logging to true and assign that valuestream to the Thing (then use QueryPropertyHistory services to pull data to display)

[riaanmarx]

Thank you PaiChung!

And does this ValueStream then replace the Integer Property I already created on the Thing, or would you then somehow bind the two so that the property only return the current value?

[PaiChung]

The property shows the value in real time.

enabling logging on the property will now store this value over time as it varies.