Call Stack size?

Question

Greetings from Michigan,

I have a program that runs continuously (logging data) where it runs inside a While loop within one Sub ("logging data" Sub), then when the log file becomes "full", it jumps to another Sub to create a new file, then jumps back to the "logging data" Sub to continue on. Anyway, it keeps doing this and can run for hours like this, creating 100+ files or more of data. The problem is that the program crashes at some point and it always crashes within this part of the program (one of these two subs, although I haven't pinpointed which one. When I run the debugger on the machine in which the program is deployed, the Call Stack is rather large. I'm wondering if that is a problem, and how is that managed. Could that be the reason for the program crashing (Call stack getting too large?). I have gotten some sort of memory exception error on at least one of the crashes. I made some edits to the code yesterday to try and alleviate this. This last crash (this morning when I got into the office) that I experienced was a nullreference exception error, although I can't pinpoint where unless I run the program from my development machine in debug mode, which I plan to do next to catch exactly what line of code the crash is happening within either of these two Subs. I'll need to run it overnight as like I said, the program can run for hours before a crash occurs. Anyway, the question is in regards to the Call Stack. Is the large Call Stack a problem? How is that managed/cleared?

Thanks, D

Public Sub dataAcquiring()
    'Receive the collection of channels in this sub and append data to each of the channels
    'Set up the channel group
    Dim message1 As String = "The data file may have been deleted or moved prior to a new data file and directory being created.  Check the main 'Data' directory and be sure the file exists, or simply create a new data file."
    Dim testBool As Boolean = False

    'Set the global variable to True if running the application from the development machine in debug mode.  Otherwise, initialize it to false for deployment.
    If Connectlocal = True Then
        statsFile = "C:\Users\dmckin01\Desktop\Data\" & folderName & "\" & dataFileName & "_stats.csv"
    Else : statsFile = "D:\Data\" & folderName & "\" & dataFileName & "_stats.csv"
    End If

    Try
        logFile.Open()
    Catch ex As Exception
        MessageBox.Show(Me, ex.Message & message1, "File not found", MessageBoxButtons.OK, MessageBoxIcon.Error)
        cbRecord.Checked = False
        Return
    End Try

    Dim i As Integer = 0, n As Integer = 0, hvar As Integer, value As Single, count As Integer = 0, maxValue As Single
    Dim b As Boolean = False, returnValue As Type, stringVar As String, lastValidNumber As Integer
    Dim dtype As System.Type
    Dim channelGroupName As String = "Main Group"
    Dim channelGroup As TdmsChannelGroup = New TdmsChannelGroup(channelGroupName)
    Dim channelGroups As TdmsChannelGroupCollection = logFile.GetChannelGroups()

    If (channelGroups.Contains(channelGroupName)) Then
        channelGroup = channelGroups(channelGroupName)
    Else
        channelGroups.Add(channelGroup)
    End If

    'Set up the TDMS channels
    Dim Names As String() = New String(13) {" Spindle Speed (rpm) ", " Oil Flow (ccm) ", " Torque (Nm) ", " LVDT Displacement (mm) ", " Linear Pot Displacement (mm) ", _
                                                     " Pneu. Actuator (0=OFF, 1=ON) ", " Elec. Actuator (0=OFF, 1=ON) ", " Hydr. Actuator (0=OFF, 1=ON) ", _
                                                     " Upper Tank Oil Temp. (°F) ", " Lower Tank Oil Temp. (°F) ", " Exit Oil Temp. (°F) ", _
                                                     " Inlet Oil Temp. (°F) ", " Part Temp. (°F) ", " Time Stamp "}
    Dim dataArrayNames As String() = New String(13) {"arrSpeed", "arrFlow", "arrTorque", "arrLVDT", "arrLinPot", "arrActPneu", "arrActElec", "arrActHydr", _
                                                     "arrUpperOil", "arrLowerOil", "arrExitOil", "arrInletOil", "arrTestPart", "arrTimeStamp"}

    Dim OPCTagNames As String() = New String(13) {"peakTorque", "peakTorqueSpeed", "peakTorquePlatePos", "timeToPeakTorque", "firstPeakTorque", "firstPeakTorqueSpeed", _
                                                "firstPeakTorquePlatePos", "timeToFirstPeakTorque", "peakDecel", "peakJerk", "engagementSpeed", "slidePlateSpeed", _
                                                "timeOfEngagement", "totalEnergy"}


    Dim bools As Boolean() = New Boolean(13) {recSpeed, recOilFlow, recTorque, recLVDT, recLinPot, recActPneu, recActElec, recActHydr, recUpperOil, recLowerOil, _
                                              recExitOil, recInletOil, recTestPart, recTimeStamp}

    'Instantiate the TDMS channels to be used.  We have to do this each and every time this Sub is executed because National Instruments
    'does not have a method to 'clear' the channel group.
    Dim ch0 As TdmsChannel = New TdmsChannel(Names(0), TdmsDataType.Float)   'spindle speed
    Dim ch1 As TdmsChannel = New TdmsChannel(Names(1), TdmsDataType.Float)   'oil flow
    Dim ch2 As TdmsChannel = New TdmsChannel(Names(2), TdmsDataType.Float)   'torque
    Dim ch3 As TdmsChannel = New TdmsChannel(Names(3), TdmsDataType.Float)   'actuator position (LVDT)
    Dim ch4 As TdmsChannel = New TdmsChannel(Names(4), TdmsDataType.Float)   'actuator position (LINEAR POT)
    Dim ch5 As TdmsChannel = New TdmsChannel(Names(5), TdmsDataType.Float) 'actuator state (pneu)
    Dim ch6 As TdmsChannel = New TdmsChannel(Names(6), TdmsDataType.Float) 'actuator state (elec)
    Dim ch7 As TdmsChannel = New TdmsChannel(Names(7), TdmsDataType.Float) 'actuator state (hydr)
    Dim ch8 As TdmsChannel = New TdmsChannel(Names(8), TdmsDataType.Float)  'upper oil tank temp
    Dim ch9 As TdmsChannel = New TdmsChannel(Names(9), TdmsDataType.Float)  'lower oil tank temp
    Dim ch10 As TdmsChannel = New TdmsChannel(Names(10), TdmsDataType.Float) 'Exit oil tank temp
    Dim ch11 As TdmsChannel = New TdmsChannel(Names(11), TdmsDataType.Float) 'Inlet oil temp
    Dim ch12 As TdmsChannel = New TdmsChannel(Names(12), TdmsDataType.Float) 'Part temp
    Dim ch13 As TdmsChannel = New TdmsChannel(Names(13), TdmsDataType.String) 'Time stamp
    Dim Channels As TdmsChannelCollection
    Dim chans As TdmsChannel() = New TdmsChannel(13) {ch0, ch1, ch2, ch3, ch4, ch5, ch6, ch7, ch8, ch9, ch10, ch11, ch12, ch13}
    Channels = channelGroup.GetChannels()

    ch0.UnitString = "RPM" : ch0.Description = "Rotational speed of the spindle shaft."
    ch1.UnitString = "CCM" : ch1.Description = "Oil flow from the specimen pump."
    ch2.UnitString = "Nm" : ch2.Description = "Torque from the torque cell."
    ch3.UnitString = "mm" : ch3.Description = "Linear displacement of the linear velocity displacement transducer."
    ch4.UnitString = "mm" : ch4.Description = "Linear displacement of the linear potentiometer."
    ch5.UnitString = "BIT" : ch5.Description = "Binary state of the pneumatic actuator (0=OFF, 1=ON)."
    ch6.UnitString = "BIT" : ch6.Description = "Binary state of the electric actuator (0=OFF, 1=ON)."
    ch7.UnitString = "BIT" : ch7.Description = "Binary state of the hydraulic actuator (0=OFF, 1=ON)."
    ch8.UnitString = "°F" : ch8.Description = "Upper tubular tank oil temperature."
    ch9.UnitString = "°F" : ch9.Description = "Lower (main) tank oil temperature."
    ch10.UnitString = "°F" : ch10.Description = "Thermocouple (Location: Remote rack, EL3318, Ch.2)."
    ch11.UnitString = "°F" : ch11.Description = "Thermocouple (Location: Remote rack, EL3318, Ch.3)."
    ch12.UnitString = "°F" : ch12.Description = "Thermocouple (Location: Remote rack, EL3318, Ch.1)"
    ch13.UnitString = "nS" : ch13.Description = "Time when the data was captured."

    'The only TDMS channels that get added to the collection are the ones that the user selects on the 'Configure Data File' form.
    'That is what this If-Then block is for. 
    If Channels.Count = 0 Then
        jArray.Clear()
        plcArrayNames.Clear()
        For Each [boolean] In bools
            If [boolean] = True Then
                Channels.Add(chans(i))
                Channels = channelGroup.GetChannels 'new
                jArray.Add(jaggedarray(i))
                plcArrayNames.Add(dataArrayNames(i))
            End If
            i += 1
        Next
    End If

    'At this point, we are ready to write data to the TDMS file.
    'Establish the line of communication to the PLC so we can read the data arrays.
    Dim tcClient As New TwinCAT.Ads.TcAdsClient()
    Dim dataStreamRead As TwinCAT.Ads.AdsStream = New AdsStream
    Dim binaryReader As System.IO.BinaryReader = New BinaryReader(dataStreamRead)

    If Connectlocal = True Then
        tcClient.Connect(851) 'local
    Else : tcClient.Connect(AMSNetID, 851)
    End If

    While cbRecord.Checked = True
        b = tcClient2.ReadAny(DRHvar, GetType(Boolean)) 'read the handshaking variable from the PLC
        If b = False Then
            'This For loop reads the appropriate arrays in the PLC and then writes that data to the appropriate arrays here.
            'The arrays in here will eventually get written to the TDMS file.
            i = 0
            n = 0
            writingData = True
            For Each [string] In dataArrayNames
                If dataArrayNames(n) = plcArrayNames(i) Then
                    hvar = tcClient.CreateVariableHandle("IO_HS.Data." & dataArrayNames(n))
                    value = 0
                    returnValue = jArray(i).GetType
                    If returnValue.Name = "Single[]" Then
                        dataStreamRead.SetLength(jArray(0).Length * 4)
                        dataStreamRead.Position = 0
                        tcClient.Read(hvar, dataStreamRead)
                        For Each [element] In jArray(0)
                            jArray(i)(value) = binaryReader.ReadSingle()
                            value += 1
                        Next
                    ElseIf returnValue.Name = "Int64[]" Then
                        dataStreamRead.SetLength(jArray(0).Length * 8)
                        dataStreamRead.Position = 0
                        tcClient.Read(hvar, dataStreamRead)
                        For Each [element] In jArray(0)
                            jArray(i)(value) = binaryReader.ReadInt64()
                            value += 1
                        Next
                    ElseIf returnValue.Name = "String[]" Then
                        dataStreamRead.SetLength(jArray(0).Length * 32)
                        dataStreamRead.Position = 0
                        tcClient.Read(hvar, dataStreamRead)
                        For Each [element] In jArray(0)
                            stringVar = binaryReader.ReadChars(32)
                            lastValidNumber = Math.Max(Math.Max(Math.Max(Math.Max(Math.Max(Math.Max(Math.Max(Math.Max(Math.Max(stringVar.LastIndexOf("0"), stringVar.LastIndexOf("1")), stringVar.LastIndexOf("2")), stringVar.LastIndexOf("3")), stringVar.LastIndexOf("4")), stringVar.LastIndexOf("5")), stringVar.LastIndexOf("6")), stringVar.LastIndexOf("7")), stringVar.LastIndexOf("8")), stringVar.LastIndexOf("9"))
                            If lastValidNumber > 0 Then
                                jArray(i)(value) = stringVar.Substring(0, lastValidNumber + 1)
                            Else
                                jArray(i)(value) = "Invalid Timestamp"
                            End If
                            value += 1
                        Next
                    End If
                    tcClient.DeleteVariableHandle(hvar)
                    i += 1
                    If i = plcArrayNames.Count Then
                        Exit For
                    End If
                End If
                n += 1
            Next

            'This For loop appends/writes the data from each array to the actual TDMS file.
            i = 0
            For Each [array] In jArray
                dtype = Channels(i).GetDataType
                If dtype.Name = "Int32" Then
                    Channels(i).AppendData(Of Integer)(jArray(i))
                ElseIf dtype.Name = "Single" Then
                    Channels(i).AppendData(Of Single)(jArray(i))
                ElseIf dtype.Name = "Boolean" Then
                    Channels(i).AppendData(Of Boolean)(jArray(i))
                ElseIf dtype.Name = "String" Then
                    Channels(i).AppendData(Of String)(jArray(i))
                End If
                i += 1
            Next

            Try
                'Call the DataAnalyzer dll to write stats of the cycle to stats CSV file.  Also plot the data of the cycle on the chart on the UI
                Invoke(Sub() DataAnalyzer.Analyze(arrSpeed, arrTorque, arrLinPot))
                Invoke(Sub() plotData())
                Invoke(Sub() DataAnalyzer.WriteData(statsFile, logFile.Path, arrTimeStamp(0), plcData.cyclesCompleted))
            Catch ex As Exception
                testBool = True
            End Try

            'Populate the datagridview cells with the data values
            dgvStats.Item(1, 0).Value = DataAnalyzer.peakTorque
            dgvStats.Item(1, 1).Value = DataAnalyzer.engagementSpeed
            dgvStats.Item(1, 2).Value = DataAnalyzer.slidePlateSpeed
            dgvStats.Item(1, 3).Value = plcData.bimbaTravSpeed
            dgvStats.Item(1, 4).Value = plcData.lastCycleTime
            dgvStats.Item(1, 5).Value = plcData.currentCycleTime
            dgvStats.Item(1, 6).Value = plcData.meanCycleTime
            dgvStats.Item(1, 7).Value = plcData.cyclesPerHr

            'NEW CODE to Evalute the elements in the arrTorque array to get the Max value recorded
            maxValue = 0
            For Each [element] In arrTorque
                maxValue = Math.Max(maxValue, element)
            Next
            If maxValue <= plcData.torqueAlrmSP And plcData.cycleStarted Then
                torqueLowCount += 1
            Else : torqueLowCount = 0
            End If

            'Let the PLC know that we received the data and are now ready for the next set (handshaking variable).
            tcClient2.WriteAny(DRHvar, True)
        End If

        'If the data count in the first column of the TDMS file exceeds the number here, then
        'close the file and create a new one, then continue to append/write data
        If Channels(0).DataCount >= 1020000 Then
            For Each channel As TdmsChannel In chans
                channel.Dispose() : channel = Nothing
            Next
            chans = Nothing
            channelGroup.Dispose() : channelGroup = Nothing
            If tcClient.IsConnected Then
                dataStreamRead.Dispose() : dataStreamRead = Nothing
                tcClient.Disconnect() : tcClient.Dispose() : tcClient = Nothing
            End If
            'Jump to the CreateNewFile Sub to create the next TDMS file
            CreateNewFile()
        End If
    End While

    If logFile.IsOpen = True Then
        logFile.Close()
    End If
    If tcClient.IsConnected Then
        dataStreamRead.Dispose() : dataStreamRead = Nothing
        tcClient.Disconnect() : tcClient.Dispose() : tcClient = Nothing
    End If
    writingData = False
End Sub

Private Sub CreateNewFile()
    'Create the new folder where the data file/s will reside
    Dim newFilename As String = dataFileName & "_" & fileNum
    Dim customFilePropertyNames() As String = {"Date"}
    Dim customFilePropertyVals() As String = {""}
    Dim newAuthor As String = logFile.Author
    Dim newDescription As String = logFile.Description
    Dim newTitle As String = logFile.Title
    Dim newPath1 As String = "C:\Users\dmckin01\Desktop\Data\" & folderName
    Dim newPath2 As String = "D:\Data\" & folderName
    fileNum += 1

    'Create the TDMS file and save it to the user specified directory
    customFilePropertyVals(0) = Date.Today.ToShortDateString()
    logFile.Close() 'Close the old logfile after we've gotten values/properties from it
    logFile.Dispose() : logFile = Nothing

    Try
        If Connectlocal = True Then
            logFile = New TdmsFile(newPath1 & "\" & newFilename & ".tdms", New TdmsFileOptions())
        Else : logFile = New TdmsFile(newPath2 & "\" & newFilename & ".tdms", New TdmsFileOptions())
        End If
    Catch ex As Exception
        MessageBox.Show("Directory not created.  Make sure the TDMS file and/or directory that you are referencing are not already currently opened.", "Directory Creation Failed", MessageBoxButtons.OK, MessageBoxIcon.Error)
        Exit Sub
    End Try
    logFile.Author = newAuthor
    logFile.Description = newDescription
    logFile.Title = newTitle
    logFile.AddProperty(customFilePropertyNames(0), TdmsPropertyDataType.String, customFilePropertyVals(0))
    logFile.AutoSave = True
    dataAcquiring()
End Sub

Answer 1

Stack errors are always caused by loops in your code that call back on themselves. Often caused by property setting handlers that set other properties that, in their turn, try to set the initial property. They can be difficult to pinpoint sometimes.

In your case, you have called the logging function

    dataAcquiring()
End Sub

At then end of the file creation routine... this is a SERIOUS bug.

Each time you start a new file you start a new instance of the log loop and the old one remains on the stack... it's just a matter of time till it runs out of room

In this instance... the create routine should just exit..

However, if it were me I would make that code a function that returns true or false. Have it return false if the file could not be created for some reason and handle it gracefully in the main loop.