Calculating last(#1) and last(#2) from the same item

[silverd]

Hi Guys

Does anyone know if its possible to calculate last(#1) and last(#2) from the same item e.g.

itemA.last(#1) - itemA.last(#2)

The value I am getting is a ever growing numeric value and I am trying calculate the diffs between the last two readings.

If so, is it possible to put this in a calculated item?

Thanks in advance for any help on this.

[storm]

do you want this to be a trigger or another item?

[silverd]

Another item would be great.

[heaje]

Why not just change the item definition to be stored as a delta. There isn't a need for a calculated item.

[silverd]

Thank you I didn't know what the stored as delta item does. I tried it and it works perfectly thank you for the advice.

[xpehbam]

There is also the prev() function.