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Rank: Advanced Member
Groups: Member
Joined: 7/16/2008
Posts: 35
Location: UK
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Hi, I am wondering if anyone has any tips for achieving the following in PI. We have a particular set of instruments which must be old/faulty and occasionally throw an error to the control system which in turn sends a maximum 16bit wordlength signal to PI (65535). This is triggering alarms everywhere and our users are desperate for this to be resolved. The simple solution would be, replace the faulty instruments/control system....of course this won't be happening anytime soon so we have been asked to omit this value (65535) each time the PI server receives it. The problem is there are 20,000 tags on this system which could potentially at any point throw up this value and trigger a false alarm. I don't think creating another 20,000 tags and using PE to output the value if it is <> 65535 would be the answer, so i am wondering if anyone can think of a clever way of doing this. FWIW there are three PI servers in this equation, one in the control network (OPC interface to a Silvertech RTD server, which in turn is fed from a Kvaerner MCS) this is then sent to a main server via PITOPI, and a third PI server runs a custom application and clones all the values yet again, and there is alarm software on this server. We have access to the PI server in teh control network and the main PI server. Does the PITOPI link give us any opportunity to filter values?? Interested to hear your responses!! Who ate all the PIs?
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 612
Location: Cheshire, United Kingdom.
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Hi Macaroni... So from my knowledge, not neccessarily correct, there is no easy way to filter values for tags or groups via OPC or PItoPI. Questions, Is your alarm software event driven on tag data or interval driven? You can probably guess that I am thinking of adding an interface to sort the data before it is picked up by alarming software. You could create a series of event pipes to the tags and lookout for the values and remove them. Obviously this wouldn't be workable if your tags are fast updating, which I suspect they are. So does the 3rd party software move all the data receving the error values, how does that work - events or polled? Rhys. Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Advanced Member
Groups: Member
Joined: 7/23/2008
Posts: 38
Location: Cheshire, UK
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Hi Macaroni...
I'm with Rhys on this one. Can't see anything on PIToPI that would allow this type of filtering.
May be an option to do something around 'Data Quality' if using OPC but thats going to depend on how the data is being sent by the particuler OPC Server you may be using.
Regards,
Burnikell1
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Rank: Advanced Member
Groups: Member
Joined: 7/16/2008
Posts: 35
Location: UK
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Thanks for the response. I didn't think this was going to be simple! As for the alarm software, I have no idea how it works (its on another server and supported by another company!) they read data from our main PI server and write it to a "cleansed" PI server so they should have the facility to filter these spikes, but the users were complaining that the cleansed data was too different from the raw data, I think they don't know how to tune it properly. The only thing I can think is that as we are pulling the values initially from a server in the control network, is it possible (without PI Ace etc) to write something that monitors the tags and deletes this erroneous value as its written to the original PI server, my thinking is that, as our PITOPI always seems to pick up the last archived value, the next time it updates, as the 655 value has vanished, the last value will be the value it archived previously. This may cause a lot of "Event exists at this time" errors...but does this sound like it may work? Would you recommend this solution? Who ate all the PIs?
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Rank: Newbie
Groups: Member
Joined: 6/3/2009
Posts: 1
Location: Indiana
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Hi Macaroni, I have pretty much the same problem you have with the nuisance values. Have you found a solution for this yet? Thanks, BW
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