6 Replies Latest reply on Jul 16, 2018 8:14 AM by Lal_Babu_Shaik

    Avoid Bad Input into PI Archive



      We have a small number of tags from a OPC HDA source that occasionally receive a 'Bad Input' value, perhaps once or twice a day when getting a reading every 5 minutes.

      Is there any way to stop these values being saved to the PI archive ?

      Cheers, Pete

        • Re: Avoid Bad Input into PI Archive

          Hi Peter


          Location5 is used to indicate how the point is to use data that has the quality of “Uncertain”.

          Data can have a quality of GOOD, Uncertain or BAD.

          0 – “Uncertain” data will be sent to PI with the questionable bit set. 

          1 – store the digital state “Bad Quality” if the quality is “Uncertain”. 

          2 – “Uncertain" quality will be treated as good quality


          If the Quality is “Bad”, then the digital state “Bad Input” will be sent to PI.

          • Re: Avoid Bad Input into PI Archive

            Hi Peter,


            Bad Input is the value written to a tag if the data received was invalid. For example, if the data received does not match the point type (trying to write a float value to integer tags) or the quality flag of the data received from the data source was “invalid”.

            So My recommendation is for you to compare the tag properties of PI tag with source tag and investigate the root cause of these "Bad Input" values.




              • Re: Avoid Bad Input into PI Archive

                Hi Vasanth,

                Tag properties are the same, it looks like it's when the instrument on the sending system has a comms fail :-


                (ignore timestamp difference as one is GMT, the other BST)

                PI Archive

                0.14300000667572 12/07/2018 13:15:00

                0.204000011086464 12/07/2018 13:29:59

                0.150000005960464 12/07/2018 13:44:59

                0.144000008702278 12/07/2018 14:00:00

                Bad Input 12/07/2018 14:11:32

                0.136000007390976 12/07/2018 14:11:36

                0.220000013709068 12/07/2018 14:15:00

                0.144000008702278 12/07/2018 14:29:59


                Source system


                12/07/2018  12:15:00  0.143000006675720 m Timed Report Good

                12/07/2018  12:30:00  0.204000011086464 m Timed Report Good

                12/07/2018  12:45:00  0.150000005960464 m Timed Report Good

                12/07/2018  13:00:00  0.144000008702278 m Timed Report Good

                12/07/2018  13:11:32  0.136000007390976 m Value Change Comm Failure

                12/07/2018  13:11:36  0.136000007390976 m Value Change Good

                12/07/2018  13:15:00  0.220000013709068 m Timed Report Good