Private Sub Process_Globals
......
Private Master As Boolean = True
End Sub
#Region Master subs
'Requests from Master to Slave with ID
'Operation: 1/2/3/4 = Read Coil Status/Read Input Status/Read Holding Registers/Read Input Registers
'Reading starting FirstRegister from registers qty of RegistersNumber
Public Sub MasterRequest(toSlaveID As Byte, Operation As Byte, FirstRegister As UInt, RegistersNumber As UInt)
Dim b(6) As Byte 'command
b(0) = toSlaveID
b(1) = Operation
Dim ui(1) As UInt
ui(0) = FirstRegister
Dim a(2) As Byte = bc.UIntsToBytes(ui)
b(2) = a(1)
b(3) = a(0)
ui(0) = RegistersNumber
Dim a2(2) As Byte = bc.UIntsToBytes(ui)
b(4) = a2(1)
b(5) = a2(0)
WriteMaster(b) 'send command + CRC
End Sub
#End region
Private Sub Receive (Buffer() As Byte)
Dim raw_len As UInt = Buffer.Length
If raw_len > 3 Then
bc.ArrayCopy2(Buffer,0,Sa,0,1)
bc.ArrayCopy2(Buffer,1,Fc,0,1)
Dim Sc As UInt = HexToInt(Fc) 'command
End If
If Not(Master) Then
If raw_len > 5 Then
bc.ArrayCopy2(Buffer,2,Fr,0,2)
bc.ArrayCopy2(Buffer,4,Nr,0,2)
Dim Sr As UInt = HexToInt(Fr) 'first register address
Dim Sn As UInt = HexToInt(Nr) 'registers qty
End If
Select Sc
Case 1
If Sr >= FCR And Sr < FCR+CO.Length Then Read_Coil_Status(Sr,Sn)
Case 2
If Sr >= FDI And Sr < FDI+DI.Length Then Read_Input_Status(Sr,Sn)
Case 3
If Sr >= FHR And Sr < FHR+HR.Length Then Read_Holding_Registers(Sr,Sn)
Case 4
If Sr >= FIR And Sr < FIR+IR.Length Then Read_Input_Registers(Sr,Sn)
Case 5
If Sr >= FCR And Sr < FCR+HR.Length Then Force_Single_Coil(Sr,Sn)
Case 16
If Sr >= FHR And Sr < FHR+HR.Length Then Preset_Multiple_Registers(Buffer,Sr,Sn)
Case Else
End Select
Else 'response from Slave
Master = False
'Log("From Slave: ", bc.HexFromBytes(Buffer))
Dim c(Buffer.Length - 2) As Byte
bc.ArrayCopy2(Buffer, 0, c, 0, c.Length)
Dim CalculatedCRC(2) As Byte = CRC(c)
'Log("Calculated CRC = ", bc.HexFromBytes(CalculatedCRC))
Dim ReceivedCRC(2) As Byte
bc.ArrayCopy2(Buffer, Buffer.Length - 2, ReceivedCRC, 0, ReceivedCRC.Length)
If bc.ArrayCompare(ReceivedCRC, CalculatedCRC) = 0 Then
Main.Modbus_NewData(c) 'pass the received data block to a needed module
Else
Log("CRC error, response was ignored")
End If
End If
End Sub
Private Sub WriteMaster(Data() As Byte)
Master = True
Dim d() As Byte = JoinBytes(Array(Data,CRC(Data)))
Log("Writing: ", bc.HexFromBytes(d))
sstream.Write(d)
End Sub
