The following code sample determines the amount of downtime, in seconds, that the Calculation collector has experienced over the last day. Downtime occurs when there are two consecutive bad
quality data points for the pulse tag. If the last known data point for the pulse tag is bad
quality, all the time between its timestamp and the current time is regarded as downtime. In
the following sample, the pulse tag is configured to be polled, with a collection interval of
one
day.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
