Examples of Calculation Formulas

Result=CurrentValue("Temp F")*(9/5)+32

Result=Calculation("Simulation00001","Average","Now-1hour","Now",Quality)

IF CurrentQuality("Simulation00001")=100 THEN 
Result=CurrentValue("Simulation00001")
END IF

Result=CurrentValue("SERVER1.Simulation00003")+CurrentValue("SERVER1.Simulation00006")

'connection and recordset variables
Dim Cnxn
Dim rsCurrentValueFromOtherServer
'open connection
Set Cnxn = CreateObject("ADODB.Connection")
'connect to default server using current username and password
'establish connection
Cnxn.Open "Provider=ihOLEDB.iHistorian.1;User Id=;Password="
'Create and open first Recordset using Connection execute
Set rsCurrentValueFromOtherServer = CreateObject("ADODB.Recordset")
'Get the value from the other server
Set rsCurrentValueFromOtherServer = Cnxn.Execute("select value from ihRawData 
where SamplingMode=CurrentValue and tagname = Simulation00001") 
'Set the result to the current value of other tag
Result=rsCurrentValueFromOtherServer("Value")
'Clean up
IF rsCurrentValueFromOtherServer.State = adStateOpen THEN
rsCurrentValueFromOtherServer.Close
END IF
IF Cnxn.State = adStateOpen THEN Cnxn.Close
END IF
Set rsCurrentValueFromOtherServer = Nothing
Set Cnxn = Nothing

Dim filesys, writefile, count,readfile
'need to create a file system object since there is no
'file I/O built into VBScript
Set filesys = CreateObject("Scripting.FileSystemObject")
'open the text file, or create it if it does not exist
set readfile = filesys.OpenTextFile("C:\somefile.txt", 1, true)
'try to read from the file
IF readfile.AtEndOfLine <> true THEN
count= readfile.ReadAll
END IF
'add one to the number stored in the count count = count+1
'close the file for reading 
readfile.Close
'open the same file but for writing
Set writefile= filesys.OpenTextFile("C:\somefile.txt", 2, true)
'write the updated count writefile.Write count
'close file for writing 
writefile.Close
Result = count

DIM X
x=CurrentValue ("tag1")
select case x
case 1
Result="one"
case 2
Result="two"
case else
Result="other"
End select

Dim MAXDIFF, TimeDiff
'Maximum difference in timestamps allowed (Must be > 2,
'units = seconds) MAXDIFF = 10
'Calculate time difference
TimeDiff = DateDiff("s", CurrentTime(), Now)
'Compare times, if difference is < MAXDIFF seconds perform calc
If TimeDiff < MAXDIFF Then
'Place calculation to be performed here:
Result = CurrentValue("DENALI.Simulation00001") Else
'Place what is to be done when no calc is performed here
Result = Null
End If

on error resume next
Dim MyServer 'As Historian_SDK.Server
Dim I
Dim J
Dim K
Dim strComment
Dim lngInterval
Dim TagCount
Dim strDataQuality
Dim iDataRecordset
Dim iDataValue
Dim lEndTime, lStartTime, lNumSamples
Dim lNumSeconds, lNumSamplesPerSecond
Dim RawMin
'Instantiate The SDK
Set MyServer = CreateObject("iHistorian_SDK.Server")
'Attempt Connection
If Not MyServer.Connect("DENALI", "administrator","") Then
result = err.description
else
Set iDataRecordset = MyServer.Data.NewRecordset
'Find the number of samples.
'build query
With iDataRecordset
.Criteria.Tagmask = "EIGER.Simulation00001"
.Criteria.StartTime = DateAdd("h",-1,Now)
.Criteria.EndTime = Now
.Criteria.SamplingMode = 4 'RawByTime
.Criteria.Direction = 1 'forward
.Fields.AllFields
'do query
If Not .QueryRecordset Then
result = err.description
End If
'Some Large number so that real samples are less
RawMin = 1000000
For I = 1 To iDataRecordset.Tags.Count
For J = 1 To iDataRecordset.Item(I).Count
Set iDataValue = iDataRecordset.Item(I).Item(J)
' if the value is good data quality
if iDataValue.DataQuality = 1 then
if iDataValue.Value < RawMin then
rawMin = iDataValue.Value
end if
end if
lNumSamples = lNumSamples + 1
Next
Next
End With
End If
Result = RawMin
'Disconnect from server
MyServer.Disconnect

You can also do this with a linked server and the Historian OLE DB provider, but this example maintains a history of the results.

Dim CostOfBarrel, BarrelsUsedToday, TotalCostToday
'Calculate the total number of barrels used over
'the previous 24hours.
BarrelsUsedToday = Calculation("BarrelsUsedTag","Total","Now 1Day","Now",Quality)
'Retrieve cost per barrel used
Dim SQLExpression
Dim Cnxn
Dim rsCurrentValue
SQLExpression = "SELECT Barrel_Cost AS Value1 FROM RawMaterial_Costs WHERE Barrel_Type = CrudeOil and
samplingmode = CurrentValue"
'open connection
Set Cnxn = CreateObject("ADODB.Connection")
'connect to default server using current username and password
'establish connection
Cnxn.Open "Provider=SQLOLEDB.1;User ID=sa; Password=;Initial Catalog=Northwind"
'Create and open first Recordset using Connection execute
Set rsCurrentValue = CreateObject("ADODB.Recordset")
'Get the value from the other server
Set rsCurrentValue= Cnxn.Execute(SQLExpression)
'Set the result to the current value of other tag
CostOfBarrel = rsCurrentValue("Value1")
'Clean up
If rsCurrentValue.State = adStateOpen then 
rsCurrentValue.Close
End If
If Cnxn.State = adStateOpen then
Cnxn.Close
End If
Set rsCurrentValue = Nothing
Set Cnxn = Nothing
'Retrieve number of barrels used
BarrelsUsedToday = Calculation("BarrelsUsed","Count","Now 1Day","Now",Quality)
'Calculate total cost of barrels today
TotalCostToday = CostOfBarrel * BarrelsUsedToday

`Get a reference to the local data archiver process object
Set RawProc = GetObject("winmgmts:Win32_PerfRawdata_Perfproc_process.name='ihDataArchiver.'")
`Scale the virtual bytes number to a value within
`the tag's EGU range
result =RawProc.PrivateBytes *.001

`Get a reference to the local data archiver process object
                Set RawProc = GetObject("winmgmts:Win32_PerfRawdata_Perfproc_process.name='ihDataArchiver.'")
`Scale the virtual bytes number to a value within the
`tag's EGU range
result =RawProc.VirtualBytes *.0001

Dim pulseTag, totalDownTime, startTime, endTime
Dim prevTime, prevQuality, lastPrevTime, lastPrevQuality 
pulseTag = "calcPulseTag"
totalDownTime = 0 
endTime = CurrentTime()
startTime = DateAdd("d", -1, endTime)
lastPrevTime = curTime lastPrevQuality = 0
Do
  'get the timestamp and quality of the tag value previous to the last one we checked
  On Error Resume Next
  prevTime = PreviousTime(pulseTag, lastPrevTime) 
  If Err.Number <> 0 Then
    'no more values for this tag exit gracefully
    Exit Do
End If
prevQuality = PreviousQuality(pulseTag, lastPrevTime)
'if we have two consecutive bad data points, add to the downtime
If prevQuality = 0 And lastPrevQuality = 0 Then
  If prevTime > startTime Then
    totalDownTime = totalDownTime + DateDiff("s", prevTime, lastPrevTime) 
Else
    totalDownTime = totalDownTime + DateDiff("s", startTime, lastPrevTime) 
End If
End If
  'store the timestamp and quality for comparison with the next values 
lastPrevQuality = prevQuality
  lastPrevTime = prevTime
Loop While lastPrevTime > startTime
Result = totalDownTime

Dim tagName, startTime, endTime
tagName = "testTag"
startTime = "Now 1Day" 
endTime = "Now"
Result = CalculationFilter(tagName, "TotalTimeGood", startTime, endTime, 100, tagName, "AfterTime", "Equal", 1)