VB.net MSComm port USB 4 port relay
I am trying to get my 4 port USB relay board to work in VB.net using the COM PORT. I found some code from a poster who has the 16 port USB relay version. When trying his code i can only get it to turn on relays 1-3 all at the same time. The product can be found here: USB 4 port relay
I was following what the guy in the post was doing to turn his on:
Quote:
"01+//" - Relay 1 is switched ON
"01-//" - Relay 1 is switched OFF
"02+//" - Relay 2 is switched ON
"02-//" - Relay 2 is switched OFF
That forum post can be found here: Post
The USB relay board is using a FTDI chip FT245RL. The datasheet can be found here
The code i am trying to use is this:
Code:
If MSComm.PortOpen = True Then
MSComm.PortOpen = False
End If
MSComm.CommPort = 6
MSComm.Settings = "9600,N,8,1"
MSComm.InputLen = 0
MSComm.RThreshold = 1
MSComm.SThreshold = 0
MSComm.PortOpen = True
'Turn relay #1 ON
MSComm.Output = "01+//"
And like i said above, it turns on relays 1-3 when using that code above.. but that code only works in VB6 anyways... :(
Then i finally got some source code from the seller for the FTDI commands:
Code:
Friend Class USB_FTDI_TEST
Inherits System.Windows.Forms.Form
Private Declare Function FT_Open Lib "FTD2XX.dll" (ByVal intDeviceNumber As Short, ByRef lnghandle As Integer) As Integer
Private Declare Function FT_OpenEx Lib "FTD2XX.dll" (ByVal arg1 As String, ByVal arg2 As Integer, ByRef lnghandle As Integer) As Integer
Private Declare Function FT_Close Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_Read Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal lpszBuffer As String, ByVal lngBufferSize As Integer, ByRef lngBytesReturned As Integer) As Integer
Private Declare Function FT_Write Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal lpszBuffer As String, ByVal lngBufferSize As Integer, ByRef lngBytesWritten As Integer) As Integer
Private Declare Function FT_SetBaudRate Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal lngBaudRate As Integer) As Integer
Private Declare Function FT_SetDataCharacteristics Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal byWordLength As Byte, ByVal byStopBits As Byte, ByVal byParity As Byte) As Integer
Private Declare Function FT_SetFlowControl Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal intFlowControl As Short, ByVal byXonChar As Byte, ByVal byXoffChar As Byte) As Integer
Private Declare Function FT_ResetDevice Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_SetDtr Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_ClrDtr Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_SetRts Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_ClrRts Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_GetModemStatus Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByRef lngModemStatus As Integer) As Integer
Private Declare Function FT_Purge Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal lngMask As Integer) As Integer
Private Declare Function FT_GetStatus Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByRef lngRxBytes As Integer, ByRef lngTxBytes As Integer, ByRef lngEventsDWord As Integer) As Integer
Private Declare Function FT_GetQueueStatus Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByRef lngRxBytes As Integer) As Integer
Private Declare Function FT_GetEventStatus Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByRef lngEventsDWord As Integer) As Integer
Private Declare Function FT_SetChars Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal byEventChar As Byte, ByVal byEventCharEnabled As Byte, ByVal byErrorChar As Byte, ByVal byErrorCharEnabled As Byte) As Integer
Private Declare Function FT_SetTimeouts Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal lngReadTimeout As Integer, ByVal lngWriteTimeout As Integer) As Integer
Private Declare Function FT_SetBreakOn Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_SetBreakOff Lib "FTD2XX.dll" (ByVal lnghandle As Integer) As Integer
Private Declare Function FT_ListDevices Lib "FTD2XX.dll" (ByVal arg1 As Integer, ByVal arg2 As String, ByVal dwFlags As Integer) As Integer
Private Declare Function FT_GetNumDevices Lib "FTD2XX.dll" Alias "FT_ListDevices"(ByRef arg1 As Integer, ByVal arg2 As String, ByVal dwFlags As Integer) As Integer
Private Declare Function FT_SetBitMode Lib "FTD2XX.dll" (ByVal lnghandle As Integer, ByVal mask As Byte, ByVal enable As Byte) As Integer
' Return codes
Const FT_OK As Short = 0
Const FT_INVALID_HANDLE As Short = 1
Const FT_DEVICE_NOT_FOUND As Short = 2
Const FT_DEVICE_NOT_OPENED As Short = 3
Const FT_IO_ERROR As Short = 4
Const FT_INSUFFICIENT_RESOURCES As Short = 5
Const FT_INVALID_PARAMETER As Short = 6
Const FT_INVALID_BAUD_RATE As Short = 7
' Word Lengths
Const FT_BITS_8 As Short = 8
Const FT_BITS_7 As Short = 7
' Stop Bits
Const FT_STOP_BITS_1 As Short = 0
Const FT_STOP_BITS_1_5 As Short = 1
Const FT_STOP_BITS_2 As Short = 2
' Parity
Const FT_PARITY_NONE As Short = 0
Const FT_PARITY_ODD As Short = 1
Const FT_PARITY_EVEN As Short = 2
Const FT_PARITY_MARK As Short = 3
Const FT_PARITY_SPACE As Short = 4
' Flow Control
Const FT_FLOW_NONE As Integer = &H0
Const FT_FLOW_RTS_CTS As Integer = &H100
Const FT_FLOW_DTR_DSR As Integer = &H200
Const FT_FLOW_XON_XOFF As Integer = &H400
' Purge rx and tx buffers
Const FT_PURGE_RX As Short = 1
Const FT_PURGE_TX As Short = 2
' Flags for FT_OpenEx
Const FT_OPEN_BY_SERIAL_NUMBER As Short = 1
Const FT_OPEN_BY_DESCRIPTION As Short = 2
' Flags for FT_ListDevices
Const FT_LIST_BY_NUMBER_ONLY As Integer = &H80000000
Const FT_LIST_BY_INDEX As Integer = &H40000000
Const FT_LIST_ALL As Integer = &H20000000
Sub SetRelays(ByVal State As Integer)
Dim lngBytesWritten As Object
Dim strWriteBuffer As Object
Dim lnghandle As Object
If FT_Open(0, lnghandle) <> FT_OK Then
Status.Text = "Error while opening"
Exit Sub
Else
Status.Text = "Open OK"
End If
If FT_SetBitMode(lnghandle, 255, 1) <> FT_OK Then
Status.Text = "Bit Bang Mode Error"
Exit Sub
Else
Status.Text = "Bit Bang Mode OK"
End If
strWriteBuffer = " "
Mid(strWriteBuffer, 1, 1) = Chr(State)
lngBytesWritten = 0
If FT_Write(lnghandle, strWriteBuffer, Len(strWriteBuffer), lngBytesWritten) <> FT_OK Then
Status.Text = "Write Failed"
Exit Sub
Else
Status.Text = "Write OK"
End If
FT_Close(lnghandle)
End Sub
Private Sub cmdRelay1ON_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdRelay1ON.Click
Call SetRelays(1)
End Sub
Private Sub cmdRelay1OFF_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdRelay1OFF.Click
Call SetRelays(0)
End Sub
Private Sub cmdRelay2ON_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdRelay2ON.Click
Call SetRelays(2)
End Sub
Private Sub cmdRelay2OFF_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdRelay2OFF.Click
Call SetRelays(0)
End Sub
Private Sub cmdAllRelaysON_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdAllRelaysON.Click
Call SetRelays(255)
End Sub
Private Sub cmdAllRelaysOFF_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdAllRelaysOFF.Click
Call SetRelays(0)
End Sub
End Class
But there are a few problems here:
(1) The relay #1 doesn't even come on when pushing the button
(2) Relay #2 works for both on and off.
(3) Both the all on and all off work.
(4) When i want to turn just relay 2 off without any others off then there is no code for that in there.
So i am confused as to how to separate each relay out with that code above and just be able to turn on any number 1-4 relay on or off independently from each other! It shouldn't be this hard! I'm pretty sure its using the Bit-Bang approach here.
Any help would be great!
David
Re: VB.net MSComm port USB 4 port relay
Use the SerialPort control in the toolbox (drop one on the design surface).
In the Form load event.
Code:
With SerialPort1
.PortName = "Com6" 'or whatever port you are using
.RTSEnable = True
.BaudRate = 9600
.Open()
End With
In a button click event (perhaps):
Code:
SerialPort1.Write("01+//")
As to the details of how the board works, or doesn't, you'll have to contact the vendor.
Dick
Re: VB.net MSComm port USB 4 port relay
Quote:
Originally Posted by
DickGrier
Use the SerialPort control in the toolbox (drop one on the design surface).
In the Form load event.
Code:
With SerialPort1
.PortName = "Com6" 'or whatever port you are using
.RTSEnable = True
.BaudRate = 9600
.Open()
End With
Dick
You can even set those up in the properties from the UI
Re: VB.net MSComm port USB 4 port relay
You can set these properties in the Property window -- however, I recommend that they be set in code. Suppose you want to change things at runtime? For example, how often might you want to use this code on a different PC, with a different PortName?
Dick
Re: VB.net MSComm port USB 4 port relay
I don't understand how a USB device, without a serial interface, can use the serial port.
Re: VB.net MSComm port USB 4 port relay
Hi Dwane,
AFAIK, this device uses a virtual serial port... My recollection is that the chipset might be Microchip, but it has been a while since I looked at it.
Dick
