Every time I send a command to the device, the device returns a reading, I put this code in a timer to perform repeatedly, each time before sending commands and accept after reading, emptying the input and output buffer,
Everything is all right at first, but after a period of time, will not be able to accept to the readings, but after an hour or two to restart the program is normal again, excuse me which encountered a similar situation, what is the problem (software or hardware), or special set some parameters to initialize serial port?

CodePudding user response:

The readings in the method DataReceived events

CodePudding user response:

Suggest you open a multi-threaded:

 
Dim SerialComm=New Threading. Thread (New Threading. ThreadStart (AddressOf Sp_Receiving)) 
SerialComm. Start () 'open thread 

 
Private Sub Sp_Receiving () 
Dim strIncoming As String 
Try 
If SerialPort1. BytesToRead & gt; 0 Then 
StrIncoming=SerialPort1. ReadExisting. ToString 'data in a read buffer 
SerialPort1. DiscardInBuffer () 

'strIncoming=SerialPort1. ReadLine. ToString 
'SerialPort1. DiscardInBuffer () 

'ListBox1. Items. The Add (Microsoft) VisualBasic) Left (strIncoming, InStr (strIncoming vbCr) - 1))' to a carriage return position number - 1 
'the ListBox1. Items. The Add (Mid (strIncoming, 1, Len (strIncoming) - 1))' length - 1 
ListBox1. Items. The Add (strIncoming) 

ListBox1. SelectedIndex=ListBox1. Items. The Count - 1 
If ListBox1. Items. Count & gt; Then 1000 
Me. The ListBox1. Items. The Clear () 
End the If 

End the If 
Catch the ex As Exception 
MessageBox. Show (ex. Message) 
End the Try 
End Sub 

CodePudding user response:

Not sure where is the position of the upper or lower machine, can get a mature software to simulate serial communication, your timing operation, to determine what the problem, then find the solution,

CodePudding user response:

Just like luo

 Private WithEvents mPort As SerialPort 
The Event RequestData () 
The Event Ready () 
The Event Interrupt () 
The Event RerequestData () 

Sub New (PortName As String, BaudRate As Integer) 
MPort=New SerialPort (PortName BaudRate) 
Try 
MPort. The Open () 
Catch the ex As Exception 
MsgBox (ex. ToString) 
End the Try 
End Sub 

Private Sub mPort_DataReceived (sender As Object, e As SerialDataReceivedEventArgs) Handles mPort. Method DataReceived 
Dim inData As String=CType (sender, SerialPort) ReadLine. TrimEnd ({CChar (vbCr), CChar (vbLf)}) 
If the inData=https://bbs.csdn.net/topics/(r_RequestData) Then 
RaiseEvent RequestData () 
ElseIf inData=https://bbs.csdn.net/topics/(r_Ready) Then 
RaiseEvent Ready () 
ElseIf inData=https://bbs.csdn.net/topics/(r_Interrupt) Then 
RaiseEvent Interrupt () 
Then ElseIf inData=https://bbs.csdn.net/topics/r_RerequestData 
RaiseEvent RerequestData () 
ElseIf inData & lt;> String. The Empty Then 
The Debug. Print (" unknown request received lower machine, [" & amp; inData & amp; "] ") 
End the If 
End Sub 

Private Sub mPort_Disposed (sender As Object, As EventArgs e) Handles mPort. Disposed 
Try 
If mPort IsNot Nothing AndAlso mPort. IsOpen Then 
Clear () 
MPort. Close () 
End the If 
Catch the ex As Exception 
End the Try 
End Sub 

Protected Friend Sub the Clear () 
Try 
MPort. BaseStream. Flush () 
Catch the ex As Exception 
End the Try 
End Sub