8 Replies Latest reply on Sep 4, 2018 3:31 PM by jspann

    Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440

    RohithRavikumar

      Hi All,

       

      I am getting the below error in one of the PI interfaces.

       

      I tried looking for some KB related to this and couldn't find any.Is this related to the change in time between the PI server and interface.The "0008" server in the error below is the PI server name.Will it be also die to time shift between OPC Server and PI interface node. All the systems are in same time zone.

       

      The interface provide timestamp to PI.

       

      8/7/2018 12:12:47.01401 PM, 0, Information, 07-Aug-18 12:12:47  OPCInt22.exe>PI-API> Warning: Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440, pilogsrv, , , , , , , , , , ,

       

      Wondering what causes such error in PI.

       

      Regards,

      Rohith

        • Re: Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440
          jspann

          Hi Rohith,

           

          You are correct that this message is thrown when there is a time difference between the Data Archive and interface node. With /ts=n the interface will apply an offset to the timestamps if needed. The warning indicates that there is a 440 second difference between the two nodes.

           

          Does the system time on both nodes show a ~7 min difference?

           

          Thanks,

          Javin

            • Re: Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440
              RohithRavikumar

              Hi Javin,

               

              Thanks for the response.The interface node and PI server are on the same time zone.And from the eventvwr system and application logs i dont see any time shift related errors on both systems.Also it is not happening frequently.

               

              By your statement " With /ts=n the interface will apply an offset to the timestamps if needed"

               

              You mean that if the interface observe any time difference at the time of sending data it will add offset to match the timestamp on the PI server?

               

              Please correct me if i am wrong.Also in some instances the offset varies from 5 sec to 440 secs.Some time even milli seconds

               

              8/28/2018 4:16:41.08601 AM, 0, Information, 28-Aug-18 04:16:41  OPCpi> 57 1> WARNING.  Negative time shift of 0.025000 seconds detected for Uniint scheduling.  ScheduleTime=1535444200.524000.  LastScheduleTime=1535444200.549000, pilogsrv, , , , , , , , , , ,

                • Re: Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440
                  Lal_Babu_Shaik

                  Hi Rohith

                   

                  Could you please check OPCInt timestamps section. If you are using Original timestamps then you should consider the time different between OPC server and PI server .

                   

                  Timestamps

                   

                  Interface Provides Timestamp: The OPC interface provides a time stamp when the data is

                  received (/TS=N).

                   

                  OPC server Provides Timestamp: The OPC interface uses the data time stamps provided by the

                  OPC server, and accounts for the offset between the OPC server and the PI server (/TS=Y).

                   

                  Timestamp for Advise Tags Only: The OPC server provides time stamps only for advise tags,

                  and the OPC interface accounts for the offset between the OPC server and the PI server. For all

                  other tags, the OPC interface provides a time stamp when the data is received (/TS=A).

                   

                  OPC Server Provides Timestamp (no offset): The OPC Server provides the timestamps for all

                  data, and the interface will not apply any time offset to these values. Data loss will occur of a

                  value is received from OPC with timestamp 10 minutes or more past the PI Server's current

                  time. (/TS=U)

                   

                  Thanks,

                  Lal

              • Re: Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440
                jspann

                One thing you may want to look out for is that if the events ever get more than 10 minutes in the future the Data Archive will discard them. KB 3015OSI8 has more info.

                • Re: Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440
                  gmichaud-verreault

                  Rohith,

                   

                  In addition to whatJavin Spann and Lal Babu Shaik have already mentioned, I would strongly recommend you to look into resolving the root cause of the issue. From the few error messages you have posted, you appear to have some clock jittering on the interface node and/or on your PI Data Archive. It is very important to make sure that all your machines are properly synced.

                   

                  Windows computers that are members of a domain will normally synchronize clocks with the domain controller, using the Windows Time Service. This synchronization is provided specifically to support time-stamping of Kerberos authentication tickets. Per Microsoft, Windows Time is not considered a high-accuracy time synchronization system, and should not be relied on if very accurate time is required. Even if the accuracy of Windows Time is considered adequate, it requires that the domain controller itself be synchronized to a high accuracy time source. In practice, this is seldom done.

                   

                  Network Time Protocol (NTP) is the internet standard for clock synchronization (see: RFC 5905). If you require higher accuracy than that provided by Windows Time, you may use an NTP client synchronizing with a public time server or with a private NTP server connected to a high accuracy time source such as a GPS clock. If NTP is used, the Windows Time service on each PI client computer must be disabled; otherwise, the computers clock may jitter between the time provided by the domain controller and the time provided by the NTP server. A jittering clock may cause data loss if existing values are overwritten or if values receive future timestamps.

                  You can refer to this article for more details on how to synchronize Windows to a NTP Server:

                  http://www.timetoolsglobal.com/2013/06/21/how-to-synchronize-microsoft-windows-to-a-ntp-server-1

                   

                  Hope this helps,

                   

                  Gabriel

                  • Re: Server(xxxxx0008.xxx.com:5450)/Client offset excessive change of -440
                    RohithRavikumar

                    Hi All,

                     

                    Thanks for all the responses.

                     

                    I reached out to windows team and hey confirmed that there was no time drifts notified during the negative time shift errors or the time off set error reported in the PIPC logs.And now i am asked to validate the application performance.

                     

                    Network team confirmed that there is no network latency absorbed between the servers.

                     

                    Its weird and now i am stuck.

                     

                    Regards,

                    Rohith

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