I am writing a VB.Net (VS 2015) application to control equipment in real time which is connected via USB ports. The equipment requires that text string, terminated by a chr(13) be sent. Most commands will get a response back. For example one command (set VALVE1 ON) will open a valve one on the equipment. When plugging the equipment in it appears as COM7 on my laptop, though I can change this via device manager, and have done so to ensure I don't get the problem just on COM7. the euipment then sends back a string to confirm valve has opened. A light also displays to show valve has opened.
When running my code the valve opens and about seven seconds later the coms port closes and the equipment locks up. If I use Hyperterminal or Docklight to send the string, then valve opens and string comes back.
I started using Framework 4.5 and the valve would not open. I now use Framework 4.6.1 and get the results described.
If I connect to another computer running Hyperterminal or Docklight then the sent string is displayed correctly and strings can be sent back to my application.
Sub SendSerialData(ByVal data As String)
' Send strings to a serial port.
Dim _continue As Boolean
Dim s As String
Dim sl As Integer
Dim rct As Integer
Dim CC As Integer
Dim incoming As String
Dim J As Integer
J = 0
Dim jl As Integer
Dim bytes() As Byte
' Dim ascii As New ASCIIEncoding()
' Create two different encodings.
Dim ascii As Encoding = Encoding.UTF8
Dim unicode As Encoding = Encoding.Unicode
' Convert the string into a byte array.
Dim unicodeBytes As Byte() = unicode.GetBytes(data)
' Perform the conversion from one encoding to the other.
Dim asciiBytes As Byte() = Encoding.Convert(unicode, ascii, unicodeBytes)
' Convert the new byte array into a char array and then into a string.
Dim asciiChars(ascii.GetCharCount(asciiBytes, 0, asciiBytes.Length) - 1) As Char
ascii.GetChars(asciiBytes, 0, asciiBytes.Length, asciiChars, 0)
Dim asciiString As New String(asciiChars)
Dim indata As String
' Send strings to a serial port.
' sending one bit at a time. Have also tried whole line at a time.
Using com1 As IO.Ports.SerialPort = My.Computer.Ports.OpenSerialPort("COM7", 115200, Parity.None, 8, StopBits.One)
com1.NewLine = Chr(13)
jl = Len(data)
Dim b As Byte
For J = 0 To Len(asciiChars) - 1
com1.Write(asciiChars(J))
Next j
MsgBox(com1.IsOpen)
_continue = True
s = ""
sl = 0
rct = 0
'
While _continue
CC = 0
Try
While com1.BytesToRead = 0 And CC < 2000
CC = CC + 1
J = com1.BytesToRead
End While
Catch ex As Exception
_continue = False
End Try
incoming = com1.ReadExisting
rct = rct + 1
If rct > 100 Then _continue = False
s = s & incoming
If Len(s) >= 1 Or rct > 1000 Then
_continue = False
sl = Len(s)
Else
' MsgBox(Len(s) & " -" & s)
End If
End While
End Using
MsgBox(rct & " - " & s & " Length " & sl)
End Sub
So has anyone had this problem and found a solution please ? I suspect it is something to do with Framework, because one version would not work and current one partially works. So far no strings returned.
Alternatively can any one point me to sending strings to USB without using Framework please ?
