9 Replies Latest reply on Mar 17, 2011 8:40 PM by RJKSolutions

    Looking for best method to query for Tag Scan Rates...

    jeffjamesmcmahon

      I am in need of a reliable method of querying the PI system for a Tag's scan rate at the interface (the /f: values from the interface's batch file).

       

      Here is the approach that I am thinking of taking...

       

      1) Use Location4 to fetch the index of /f

       

      2) Query the MDB for \\servername\Modules\%OSI\Interfaces\servername\interfacename\Properties\Arguments - i see there are /f{1}, /f{2} etc

       

      I have several questions around this technique:

      1. Is it the correct path to take ?
      2. Is there a guarantee that all of the installed interfaces will be available using this technique ? (I don't see the Random interface when i look through MDB using PI SMT->Operation->ModuleDatabase... and I know its being used for the default points.)

      Thanks !

       

      Jeff

       

       

        • Re: Looking for best method to query for Tag Scan Rates...

          The ICU configuration utility updates the MDB with the command line of the interface.  The interface may be set up without using ICU.  If that is the case (random) then no information will be available.  Your site may be standardized so that such exceptions are not expected.  UNIX based interfaces are also excluded from the MDB listing.  Also, some interfaces may not fit the standard UNIINT command line model.  It is unusual, but possible.

           

          The interface team has discussed using other methods than an index into a locally stored list of scan frequencies (location4 pointing to a list of /f values), but I am not familiar with proposed implementations.

           

          I will point an interface developer to your question and see what they say.

            • Re: Looking for best method to query for Tag Scan Rates...

              @Jeff: in the nicest way possible, I would like to point out that PI System administration questions are generally better handled by our regular Technical Support team (rather than vCampus, which focuses on PI Programming and systems integration questions). They have the formal processes/mechanisms to involve escalation people (and Interface developers themselves, if need be), to get your questions answered.

               

              This is true for end-user questions as well (e.g. using PI DataLink or PI ProcessBook, etc.).

               

              But when it comes to PI Programming or integration of the PI System with other systems, then vCampus is definitely the right place! Just trying to help you get the right answers in the most timely fashion.  ;)

                • Re: Looking for best method to query for Tag Scan Rates...
                  jeffjamesmcmahon

                  Steve,  Thanks for the tip. In this case, we are building an analytics application that would benefit from "knowing" the tag's scan rate - and we are using the PI.SDK to try to get to the scan rates so I figured I was posting in the correct location.

                   

                  Perhaps I should have been clearer in the original post...

                   

                  Jeff

                    • Re: Looking for best method to query for Tag Scan Rates...

                      Hehe, I see :)  No worries anyways, just trying to help you make the most out of all the available resources.

                       

                      In this case, if you are using PI SDK, you will have to fall back to reading the PI Module Database; if the PI Random Simulator Interface doesn't appear under the PI Module Database, it's because it hasn't been loaded in PI ICU yet (as pointed out by Charlie).

                        • Re: Looking for best method to query for Tag Scan Rates...
                          tcantele

                          I concur with @Charles first paragraph. The method you propose should work for all of your Windows based interfaces that were configured using the ICU. As far as plans for using another method for storing the scan frequencies, the current method is not going to change until a new interface framework is released.

                            • Re: Looking for best method to query for Tag Scan Rates...
                              jeffjamesmcmahon

                              Thanks for the replies !  I appreciate the effort to compile these speedy reply !

                               

                              Can anyone comment on the nature of the current PI installations Re: the flavours of interfaces (Windows / Unix/ Linux) and how common it would be to use the ICU tool for deployment of PI Interfaces in the wild ?

                               

                              The tool we are building is a third party offering to existing PI Users and I am trying to understand how complete/reliable the ModuleDB approach would be for current PI Customers.

                               

                              Can anyone ballpark a percentage of tags that would be covered by this approach ?

                                • Re: Looking for best method to query for Tag Scan Rates...
                                  Ahmad Fattahi

                                  Unix/Linux interfaces are used but do not make a significant portion of all PI interfaces out there. As for Windows interfaces, it is hard to put a number on what percentage of them are configured using the ICU; however, it is the common practice. In other words, my sense is that a strong majority of Windows interfaces are set up via ICU.

                                    • Re: Looking for best method to query for Tag Scan Rates...

                                      As Ahmad pointed out, I think most Windows Interfaces (the vast majority) are being handled through PI ICU. Simply, people tend not to load the PI Random Simulator, PI RampSoak Simulator and PI Performance Equations, which come by default with the PI Server.

                                       

                                      Most people don't do a lot of work with the 2 simulators, but if you are testing stuff and you need more simulated points, then you will use them and loading them in PI ICU will be of great help (like in this case).

                                       

                                      As for loading the PI Performance Equations scheduler in PI ICU, it allows for easier management of the scan classes, it makes it easy to create additional instances of the scheduler (in case of really, really high load), and it makes the Points > Performance Equations plug-in in SMT more easy to use (i.e. drop-down list for scan classes, rather than text box).

                                  • Re: Looking for best method to query for Tag Scan Rates...

                                    Tony Cantele

                                    ...the current method is not going to change until a new interface framework is released.

                                     

                                     

                                    With the dawn of PI Server 2010 (i.e. reliance on AF) and phasing out of MDB I can only assume that AF is going to form part of such a future interface framework?  We already see a "Configuration" AF database and I remember discussions about connections being stored in AF too.  Create a few interface (ICU) Element Templates and away you go OSI...

                                     

                                    (sorry, didn't have anything relevant to add to the actual discussion)