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Rank: Newbie
Groups: Member
Joined: 5/23/2010
Posts: 8
Location: Nottingham
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Hi, gents.
I need a little help. I've procuced a Label display calculated via the calculation below - which is label4. I need to us the result/reading from this label to produce a rolling line graph on a processbook display screen.
Can anyone help?
Cheers.....Chris
FREQC = Value16.GetValue(dte, Status)
PNMOD = Value63.GetValue(dte, Status)
Label4.Caption = Format(PNMOD + FREQC, "0.0 MW")
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 617
Location: Cheshire, United Kingdom.
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Hi Chris, Welcome to the forum. Are you just reading in data from PI Points in "Value16" and "Value63"? If so, you can create a Data Set (PI Calculation) that you can use on a Trend. Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Newbie
Groups: Member
Joined: 5/23/2010
Posts: 8
Location: Nottingham
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Yes, I thought so. Its just that the two tags are on different PI servers. What would the PI calculation be?
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Rank: Newbie
Groups: Member
Joined: 5/23/2010
Posts: 8
Location: Nottingham
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Just a bit of an update....I've worked out the PI calculation to add to tags together which are on the same server.....but there dont seem to be any way I can add two tags together on different servers? Surely there must be a way to maybe add a server address/identification to each tag which is to be added?
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Rank: Newbie
Groups: Member
Joined: 5/23/2010
Posts: 8
Location: Nottingham
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Ha, I know it seems I'm having a conversation with myself here....but here is another update.
Aparently you cant easily write a dataset using tags off of 2 different servers....so the calculation has to be done in Visual Basic. This is the code I have come up with
'Frequency Corrected Power
FREQC = Value16.GetValue(dte, Status)
PNMOD = Value63.GetValue(dte, Status)
Label4.Caption = Format(PNMOD + FREQC, "0.0 MW")
The question is how do I produce an auto updating/scrolling graph with the result generated in Label4?
Sorry to be a pain.....Chris
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Rank: Advanced Member
Groups: Member
Joined: 5/28/2009
Posts: 75
Location: Cheshire, UK
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Hi Chris, I was just composing a note but you beat me to it. I came to the same conclusion that it cant be doen (easily) as the datasets are probably calculated on the server holding the tag & data. With Excel (with or without VBA) this could be done though. I thought! But do the data points have corresponding timestamps? Or must it be in ProcessBook? Miles MilesUK
ProcessBook v3.0.15.3
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Rank: Newbie
Groups: Member
Joined: 5/23/2010
Posts: 8
Location: Nottingham
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No it has to be in processbook. It is for a display in our control room which is part of a plant overveiw screen.
Cheers
Chris
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 617
Location: Cheshire, United Kingdom.
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Hi Chris, (Hi Miles) So as you found out, a PI Calculation data set is based on Performance Equation syntax, which is tied to a single server. Your options would be: - Use PItoPI to get the neccessary values from PI Server 'B' to PI Server 'A' and run a Performance Equation on PI Server 'A'. - Use PI-ACE to connect to the 2 PI Servers and perform the calculation outputing the result to either or both servers. - Use ODBC datasets to connect to an Excel Spreadsheet where you collect & calculate the result you need (e.g. via PISDK, Datalink). - Use ODBC datasets to connect to SQL Server where you have a Linked Server (via PI-OLEDB) to both PI servers. Using ODBC dataset to connect to Excel is quite easy but it depends on how you want to go. Is it beneficial to historise the value of you calculation rather than seeing the results ad hoc when you open the display? Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Newbie
Groups: Member
Joined: 5/23/2010
Posts: 8
Location: Nottingham
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I suppose it would be beneficial, but the main outcome needs to be a scrolling graph in the control room displaying the previously mentioned Label4.
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