MSComm: data not received

[Mas Juliza Alias]

I have prepared the below coding to receive data from rs232 serial port.

Option Explicit
 
Dim Port As String
Dim BRate As String
Dim DBits As String
Dim Parity As String
Dim SBits As String
Dim Flow As String
 
Private Sub cboBRate_Change()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboBRate_Click()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboBRate_KeyDown(KeyCode As Integer, Shift As Integer)
    On Error Resume Next
    If KeyCode = 38 Then
        Let cboPort.SelStart = 0
        cboPort.SetFocus
    ElseIf KeyCode = 40 Then
        Let cboDBits.SelStart = 0
        cboDBits.SetFocus
    End If
End Sub
 
Private Sub cboBRate_KeyPress(KeyAscii As Integer)
    On Error Resume Next
    If KeyAscii = 8 Or KeyAscii = 48 Or KeyAscii = 49 Or KeyAscii = 51 Or KeyAscii = 52 Or KeyAscii = 53 Or KeyAscii = 54 Or KeyAscii = 55 Or KeyAscii = 56 Or KeyAscii = 57 Then
        MsgBox "Please enter number only!", vbExclamation
        Let cboBRate.SelStart = 0
        Let cboBRate.SelLength = 20
        cboBRate.SetFocus
    End If
End Sub
 
Private Sub cboDBits_Change()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboDBits_Click()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboDBits_KeyDown(KeyCode As Integer, Shift As Integer)
    On Error Resume Next
    If KeyCode = 38 Then
        Let cboDBits.SelStart = 0
        cboDBits.SetFocus
    ElseIf KeyCode = 40 Then
        Let cboParity.SelStart = 0
        cboParity.SetFocus
    End If
End Sub
 
Private Sub cboDBits_KeyPress(KeyAscii As Integer)
    On Error Resume Next
    If KeyAscii = 8 Or KeyAscii = 48 Or KeyAscii = 49 Or KeyAscii = 51 Or KeyAscii = 52 Or KeyAscii = 53 Or KeyAscii = 54 Or KeyAscii = 55 Or KeyAscii = 56 Or KeyAscii = 57 Then
        MsgBox "Please enter number only!", vbExclamation
        Let cboDBits.SelStart = 0
        Let cboDBits.SelLength = 20
        cboDBits.SetFocus
    End If
End Sub
 
Private Sub cboParity_Change()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboParity_Click()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboParity_KeyDown(KeyCode As Integer, Shift As Integer)
    On Error Resume Next
    If KeyCode = 38 Then
        Let cboDBits.SelStart = 0
        cboDBits.SetFocus
    ElseIf KeyCode = 40 Then
        Let cboSBits.SelStart = 0
        cboSBits.SetFocus
    End If
End Sub
 
Private Sub cboPort_Change()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboPort_Click()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboPort_KeyDown(KeyCode As Integer, Shift As Integer)
    On Error Resume Next
    If KeyCode = 40 Then
        Let cboBRate.SelStart = 0
        cboBRate.SetFocus
    End If
End Sub
 
Private Sub cboSBits_Change()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboSBits_Click()
    Let cmdApply.Enabled = True
End Sub
 
Private Sub cboSBits_KeyDown(KeyCode As Integer, Shift As Integer)
    On Error Resume Next
    If KeyCode = 38 Then
        Let cboParity.SelStart = 0
        cboParity.SetFocus
    End If
End Sub
 
Private Sub cboSBits_KeyPress(KeyAscii As Integer)
    On Error Resume Next
    If KeyAscii = 8 Or KeyAscii = 48 Or KeyAscii = 49 Or KeyAscii = 51 Or KeyAscii = 52 Or KeyAscii = 53 Or KeyAscii = 54 Or KeyAscii = 55 Or KeyAscii = 56 Or KeyAscii = 57 Then
        MsgBox "Please enter number only!", vbExclamation
        Let cboSBits.SelStart = 0
        Let cboSBits.SelLength = 20
        cboSBits.SetFocus
    End If
End Sub
 
Private Sub cmdApply_Click()
    On Error Resume Next
    If MSComm1.PortOpen Then
        MSComm1.PortOpen = Not MSComm1.PortOpen
        MSComm1.CommPort = Val(Mid(cboPort.Text, 4, 1))
        MSComm1.Settings = Val(cboBRate.Text) & "," & Left(cboParity.Text, 1) & "," & Val(cboDBits.Text) & "," & Val(cboSBits.Text)
        With cboFControl
            If .Text = "None" Then
                MSComm1.Handshaking = comNone
            ElseIf .Text = "Xon / Xoff" Then
                MSComm1.Handshaking = comXOnXoff
            ElseIf .Text = "RTS" Then
                MSComm1.Handshaking = comRTS
            ElseIf .Text = "RTS Xon / Xoff" Then
                MSComm1.Handshaking = comRTSXOnXOff
            End If
        End With
    End If
    Let cmdApply.Enabled = False
    cmdOK.SetFocus
End Sub
 
Private Sub cmdCancel_Click()
    Let cboPort.Text = Port
    Let cboBRate.Text = BRate
    Let cboDBits.Text = DBits
    Let cboParity.Text = Parity
    Let cboSBits.Text = SBits
    Let cboFControl.Text = Flow
    Hide
End Sub
 
Private Sub cmdOK_Click()
    On Error GoTo No_Receive
    If MSComm1.PortOpen Then
        MSComm1.PortOpen = Not MSComm1.PortOpen
        MSComm1.CommPort = Val(Mid(cboPort.Text, 4, 1))
        MSComm1.Settings = Val(cboBRate.Text) & "," & Left(cboParity.Text, 1) & "," & Val(cboDBits.Text) & "," & Val(cboSBits.Text)
        With cboFControl
            If .Text = "None" Then
                MSComm1.Handshaking = comNone
            ElseIf .Text = "Xon / Xoff" Then
                MSComm1.Handshaking = comXOnXoff
            ElseIf .Text = "RTS" Then
                MSComm1.Handshaking = comRTS
            ElseIf .Text = "RTS Xon / Xoff" Then
                MSComm1.Handshaking = comRTSXOnXOff
            End If
        End With
    End If
No_Receive:
    MsgBox "Error receiving the data. Check your comm. port.", vbExclamation
End Sub
 
Private Sub Form_Activate()
    On Error Resume Next
    Let cmdOK.Default = True
    Let cmdApply.Enabled = False
    Let Port = cboPort.Text
    Let BRate = cboBRate.Text
    Let DBits = cboDBits.Text
    Let Parity = cboParity.Text
    Let SBits = cboSBits.Text
    Let Flow = cboFControl.Text
    cboPort.SetFocus
End Sub
 
Private Sub Form_Load()
    Dim i As Integer, j As Integer, k As Double
    Let Caption = "Real-time elevation via comm. port"
    Let cmdCancel.Cancel = True
    Let cboPort.Text = "COM1"
    For i = 1 To 4
        cboPort.AddItem "COM" & i
    Next i
    With cboBRate
        .Text = 9600
        .AddItem "110"
        .AddItem "300"
        .AddItem "600"
        .AddItem "1200"
        .AddItem "2400"
        .AddItem "4800"
        .AddItem "9600"
        .AddItem "14400"
        .AddItem "19200"
        .AddItem "28800"
        .AddItem "38400"
        .AddItem "56000"
        .AddItem "57600"
        .AddItem "115200"
        .AddItem "128000"
        .AddItem "256000"
    End With
    Let cboDBits.Text = 8
    For j = 4 To 8
        cboDBits.AddItem j
    Next j
    With cboParity
        .Text = "None"
        .AddItem "Even"
        .AddItem "Odd"
        .AddItem "Mark"
        .AddItem "Space"
    End With
    Let cboSBits.Text = 1
    For k = 1 To 2 Step 0.5
        cboSBits.AddItem k
    Next k
    With cboFControl
        .Text = "None"
        .AddItem "RTS"
        .AddItem "RTS Xon / Xoff"
        .AddItem "Xon / Xoff"
    End With
 
End Sub
 
 
Private Sub MSComm1_OnComm()
    Dim strRTL As String
    'If MSComm1.CommEvent = comEvReceive Then
    '    RTData = MSComm1.Input
    '    lstDataLog.List = RTData
    'End If
 
    ' Returns communication event or error
    Select Case MSComm1.CommEvent
        Case comBreak
        Case comEventFrame
        Case comEventOverrun
        Case comEventRxOver
        Case comEventRxParity
        Case comEventTxFull
        Case comEventDCB
 
        Case comEvCD
        Case comEvCTS
        Case comEvDSR
        Case comEvRing
        Case comEvReceive
        Case comEvSend
        Case comEvEOF
    End Select
    ' Store fetched data in a variable
    strRTL = MSComm1.Input
    txtDataLog.Text = strRTL
 
End Sub
 

There are two tabs in the form (see attachment) where the 'Comm port properties' tab is for the setting and the 'Data logger' tab is for data display. I planned to develop a hyperterminal-like program that can receive and display the transmitted data from a tide gauge device. But somehow my codes don't work. I don't have idea to fix the code so that the data can be received and displayed in a text box (txtDataLog) on data logger tab. I tried using Hyperterminal to see whether the device itself not transmitting the data, but the data are received and displayed accordingly in the program window. Please anyone can tell me what is missing in my codes...
Thank YOU in advance.

[Guido Geurs]

I have no experience in COM ports but here are some questions:
- What device is it ? company, type, ...
- Do you have documentation on how to connect the device and communicate with it?
- can you contact someone of that company who can give you advice on the protocols for establishing a communication?

[Guido Geurs]

Maybe these are stupid remarks but:
- why are the settings like Bit-rate and parity in a Combobox?
If this is a program for only one device, then there is no need for multiple selection of a parameter.
Or is this a program for different types of devices?

PS:
Just a suggestion:
When you have to test a program with trails and errors,
keep the code as simple a possible.
Just use one button and write the code directly in the variable like:
MSComm1.Settings = "9600,n,8,1"
If this works, you know you are on the right track and then you can expand your code with features like comboboxes with multiple possibilities.

[Mas Juliza Alias]

Thank you for the reply. The device is for measuring the water level, called as Portable Tide Gauge, Valeport Model 780. I wrote the coding for serial communication referred to internet search and previous papers related to it. I once read that this MSComm can receive any device signal as long as the parameters are the same. I use combo boxes for all the parameters since the program may receive data from other tide gauge devices with different model or brand from the one I am using for testing. I have tried using MSComm1.Settings = "4800,n,8,1" (same parameters setting with the device) but still, I get the same result; error MsgBox of No_Receive appears as I click OK. Is the line position of On Error GoTo No_Receive has something to do with this? Normally where do you put the error debugging line?

[Guido Geurs]

Is it possible to attach the Form in Bytes so we can work on the same code ?

[Mas Juliza Alias]

Attached is the form for the serial port communication. Thanks for your time.

[Guido Geurs]

I have some questions:
Q1 - You set comboboxes with predefined values.
Why must the user enter a value?

    With cboBRate
        .Text = 9600
        .AddItem "110"
        .AddItem "300"
        .AddItem "600"
.....
Private Sub cboBRate_KeyPress(KeyAscii As Integer)
    On Error Resume Next
    If KeyAscii = 8 Or KeyAscii = 48 Or KeyAscii = 49 Or KeyAscii = 51 Or _
                  KeyAscii = 52 Or KeyAscii = 53 Or KeyAscii = 54 Or KeyAscii = 55 Or _
                  KeyAscii = 56 Or KeyAscii = 57 Then
        MsgBox "Please enter number only!", vbExclamation

Q2 - why deactivating the "Apply" button?
Even if the values of the comboboxes are set to a default value for a communication (can be saved to a "Settings.ini" file) then the user has to click on a combobox to activate the button.

Q3 - "KeyAscii = 8" is nothing !

Q4 - there is a difference between Keycode and keyAscii !
keycode is a code like = vbKeyLButton, ...
KeyAscii is the ASCII value of a ASCII charset like 40="(" and 41=")", ...

Q5 - The select case has no meaning

    Select Case MSComm1.CommEvent
        Case comBreak
        Case comEventFrame
        Case comEventOverrun
        Case comEventRxOver
        Case comEventRxParity...
 

PS:
To make a communication with the port You have to initialise it like the example in the VB help=

   ' Buffer to hold input string
   Dim Instring As String
   ' Use COM1.
   MSComm1.CommPort = 1
   ' 9600 baud, no parity, 8 data, and 1 stop bit.
   MSComm1.Settings = "9600,N,8,1"
   ' Tell the control to read entire buffer when Input
   ' is used.
   MSComm1.InputLen = 0
   ' Open the port.
   MSComm1.PortOpen = True
   ' Send the attention command to the modem.
   MSComm1.Output = "ATV1Q0" & Chr$(13) ' Ensure that 
   ' the modem responds with "OK".
   ' Wait for data to come back to the serial port.
   Do
      DoEvents
   Buffer$ = Buffer$ & MSComm1.Input
   Loop Until InStr(Buffer$, "OK" & vbCRLF)
   ' Read the "OK" response data in the serial port.
   ' Close the serial port.
   MSComm1.PortOpen = False

[Guido Geurs]

I don't think it's a good idea to put values for the comboboxes in the code because when you want to add or change a value, you have to open the code and compile it again.
Also you must upgrade each PC with that program.
It's better to fill the comboboxes with there values from an extern file like "settings.ini" or something like that.
It gives also the user the possibility to change values or delete or add values.
It's also more user friendly if you set the most used values as default values in an file which is loaded at startup of the program.

[Guido Geurs]

I have visited the site of Valeport "http://valeport.co.uk/Support/DownloadsandFAQs.aspx" but can't find the "Model 780" ! is this correct?

On the site you can find software and manuals for the products:
################################
Product Category FAQs Software Download Manuals / Documentation Download
Tide Gauges General Tide Gauge FAQs
TideMaster
Model 740
MIDAS WLR

Model 710

Model 730T


Pressure Sensor
TideMaster
Model 740
MIDAS WLR

Model 710

Model 730T


TideMaster
Model 740
MIDAS WLR (Hardware)
MIDAS WLR (Software)
Model 710 (Hardware)
Model 710 (Software)
Model 730T
MiniTide (Hardware)
MiniTide (Software)
####################################

[Mas Juliza Alias]

Sorry, my mistake. It is Model 740. Portable Tide Gauge Model 740.