on Feb 8, 2018Under Review - Researching
Score114
Originally posted on UserVoice
As a developer, I would like the analysis service to support custom functions that I write using AF SDK.
Custom functions for the analysis service
- Comment • 7
As a developer, I would like the analysis service to support custom functions that I write using AF SDK.
A quick solution could be, providing a Analytics Function to trigger an external script from a script folder. By default when the script is triggered, it should provide the Asset Context & Time Context to the script, Also it should have additional placeholder to pass custom information to the script. Then Write you script in Powershell, Python, R; use AFSDK, WebAPI, SQL DA, as per one's comfortably.
I've worked with customers who have expressed the same desire. They want to do some basic pre-calculations on many of the incoming data streams across the AF database, e.g., quality checks like badval or range limits and/or some basic pre-processing like moving average with a time window defined in an attribute. It can get tedious having to copy paste all of these lines of expressions from one template to another for many attributes. It would be easier to build a predefined function of their own where they just need to add the attribute name and few parameters like time range.
There have been requests for both user defined functions that only use a set of the included Analysis functions (this might be a good first step) and custom functions written in some programmatic language similar what was done in ACE.
Customer would like to have the following possibility:
During the installation of a new Analyses service kit pointing to a PI AF server where an analysis service is already configured, he would like to prevent the current PI analyses service from stopping during the installation so that no real-time data calculation is lost.
He suggested this because he would like to keep his current analysis service running without forcing it to stop despite this new installation.
Not sure why we have PI Square enhancement requests here as well., but Steve updated this Uservoice post today: Custom functions for the analysis service – Customer Feedback for OSIsoft & the PI System . This will be implemented with Matlab in AF 2.10.
I appreaciate the step back! While Matlab provides scaleability performance and capabilities on the high-end of the spectrum, there is still a demand on the lower end.
I do understand the complexities and pitfalls involved (remember Custom DR's), but there should / could be a midway, just like PI Vision seems to strike a midway with it's extensibility. E.g. leaving the data delivery to the custom function to the analysis service, but having the capability to use e.g. C# to implement custom functions within that limited frame.After all we don't want to go back to the days where we open, render and parse Excel files in an ACE module...
Update: This may not be relevant to all subscribers of this idea. Previously we informed via a status update that native MATLAB integration is now available in the 2018 release. This integration will no longer be included with the PI Server starting with PI Server 2018 SP2 release. Please see status on https://feedback.osisoft.com/forums/555148-pi-server/suggestions/17742490-custom-functions-for-the-analysis-service for more details.
I liken this to the custom function builds in Excel. Simple code defines the inputs and calculations. The function appears in the library and can be used in analytics, i.e.
customfunction('attribute1','attribute2','time1','time2')
This would be supplemental to using templates, allowing more flexibility as to where / when the function could be used.