Archive Problem (15 min average values)

[cpollak]

Dear fellow WinCC-users,


I am asking for help with the following problem. What I basically want to do is the following: For a given project with readily set-up datapoint-types and datapoints (all float measured values) and archiving (100 ms), I would like to add a new archive with 15 minute average values.

When setting up archive compression (in system management, see attached pdf), I am only able to make new datapoint-types for which i can parameterize the compression mode.

Is there a possibility to do so for existing DP-types (as also shown in the pdf)?

As a further step, I would like to automatically delete the 100-ms-values once a month and only keep the 15-minute-values. Is that possible?


Thank you very much in advance for your help! https://www.winccoa.com/fileadmin/image ... rchive.pdf

[fmulder]

Yes, both your questions can be answered with yes.

Assume you have a datapoint type with an element called 'Value'

* Add a new dp element called 'Value15' to your datapoint type
* Give this 'Value15' a statistical datapoint fucntion. Select average, a time of 15 minutes and select your previous element 'Value' as input. Your Value15 will now update every 15 minutes and will then display the 15 minute average of 'Value'
* Also, add an archive config to this element 'Value15'.

For your second question
* Asume 'value' is archived in 'archive1'
* Configure 'Value15' to be stored in a different archive
* Setup your first archive to be deleted after a month (example: change an archive every day, and only keep 30 archives)

Hope this helps. Good luck

Frenk

[cpollak]

Thank you very much for you fast response! I will have a look into it.

[leoknipp]

Hello,

if you want to use compressed values (calculated by statistical functions) please use the standard naming convention for WinCC OA.
The compression levels get the the name C + number of level, e.g. C1, C2, C3 ....
The dp-element then gets the name for the statistical function, e.g. .AVG_WT0, MIN, MAX, .....

This has the advantage that WinCC OA standard functionality, which is using compression structures, can use this structures.

Best Regards
Leopold Knipp
Senior Support Specialist

[fmulder]

Yes, the standard functions will call it C1, C2, C3 etc..
However, it is no (technical) problem to define your own dp element (with your own name) and give it a statistical function.

Good luck

Frenk

[aorange]

hmm here is a curve-ball, I have used both of these methods to achieve what the OP has asked for and would like to know which one is better from a performance point of view. Do they both use exactly 1 event per value update? which is better from a memory perspective?

[leoknipp]

Hello,

I do not know which methods you are talking about.
For the calculation of statistical functions it does not make difference which names the dp-elements have.

Best Regards
Leopold Knipp
Senior Support Specialist