Using VISUAL STUDIO 2015 VB with ADU USB Data Acquisition Products

Using VISUAL STUDIO 2015 VB with ADU USB Data Acquisition Products

View the ADU series of USB based Data Acquisition Products

Introduction

Communicating with USB devices in Visual Studio, or virtually any application software, involves a few simple steps. Unlike RS232 based devices which are connected to physical COM ports, USB devices are assigned a logical handle by operating systems when they are first plugged in. This process is known as enumeration. Once a USB device has been enumerated, it is ready for use by the host computer software. For the host application software to communicate with the USB device, it must first obtain the handle assigned to the USB device during the enumeration process. The handle can be obtained using an open function along with some specific information about the USB device. Information that can be used to obtain a handle to a USB device include, serial number, product ID, or vendor ID. Once the handle is obtained, it is used to allow the application to read and write information, to and from, the USB device. Once the application has finished with all communication with the USB device, the handle is closed. The handle is generally closed when the application terminates.

The AduHid DLL provides all the functions to open a handle, read and write data, and close the handle of ADU USB devices. The ADUHID dll can be used directly from a Visual Basic .NET application including Visual Studio 2015.

The sample program below is a rendition of our AduHidTest program demonstrating the proper method to utilize the functions within the ADUHID dll to communicate with ADU, USB based data acquisition products. The example also includes use of the functions ADUCount, GetADU and GetAduDeviceList which are new to the ADUHID and ADUHID64 dll's Ver 2.1.

The resulting executable was tested under Windows 7 and 10. All source code is provided so that you may review details that are not highlighted here.

Figure 1. AduHidTest Visual Studio 2015 VB version

IMPORTANT: The sample program provided requires access to the ADUHID DLL. To enable this you should run the Visual Studio environment with Administrator privileges. To open Visual Studio 2015 with Administrator privileges, right click the program icon and select :Run As Administrator. See Figure 2.

Figure 2: Starting Visual Studio 2015 using Right Click to Run as administrator

Lets have a look at the code......

For Visual Studio to have access to the functions inside the AduHid dll the individual functions must be declared outlining the syntax and data formats used by each function.

Module1 in our program declares all the functions to be called by the application. In the example shown, the AduHid64.dll is referenced. Note that in the 32 bit version, the AduHid.dll ( 32 bit version) is referenced. Note that specific details of the individual functions are available in the ADU On-line SDK.

(Small text used to make it fit the web page....full size text in the sample code download below !)

Option Strict Off
Option Explicit On

Module Module1

Structure ADU_DEVICE_ID
Dim iVendorId As Short
Dim iProductId As Short

<VBFixedString(7), System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.ByValTStr, SizeConst:=7)> Public sSerialNumber As String
End Structure

Declare Function OpenAduDevice Lib "AduHid64.DLL" (ByVal iTimeout As Integer) As Integer

Declare Function WriteAduDevice Lib "AduHid64.DLL" (ByVal aduHandle As Integer, ByVal lpBuffer As String, ByVal lNumberOfBytesToWrite As Integer, ByRef lBytesWritten As Integer, ByVal iTimeout As Integer) As Integer

Declare Function ReadAduDevice Lib "AduHid64.DLL" (ByVal aduHandle As Integer, ByVal lpBuffer As String, ByVal lNumberOfBytesToRead As Integer, ByRef lBytesRead As Integer, ByVal iTimeout As Integer) As Integer

Declare Function CloseAduDevice Lib "AduHid64.DLL" (ByVal iOverlapped As Integer) As Integer

Declare Function ShowAduDeviceList Lib "AduHid64.DLL" (ByRef pAduDeviceId As ADU_DEVICE_ID, ByVal sPrompt As String) As Integer

Declare Function OpenAduDeviceBySerialNumber Lib "AduHid64.DLL" (ByVal pSerialNumber As String, ByVal iTimeout As Integer) As Integer

Declare Function ADUCount Lib "AduHid64.DLL" (ByVal iTimeout As Integer) As Integer

Declare Function GetADU Lib "AduHid64.DLL" (ByRef pAduDeviceId As ADU_DEVICE_ID, ByVal iIndex As Integer, ByVal iTimeout As Integer) As Integer

End Module

The Standard Controls

The Standard Controls, function identical to the AduHidTest software. There are four buttons available to Open, Write, Read, and Close, and, two text boxes for Data To Send and Received Data. The OPEN button retrieves the handle for the first ADU device it sees using the Ontrak Vendor ID. If you have more than one ADU connected, see below section on Selective Open Controls.

Once the handle is obtained, the command to send to the ADU is typed into the Data To Send text box, and the Write button is pressed to send the command to the ADU. If the command is sending a response, the Read button can now be activated and the data read back will be displayed in the Received Data text box. The Close button can then be pressed to close the handle to the ADU.

Figure 3: The Standard Controls

Here are the subroutines for each element and a few comments.

The Open button

Dim aduHandle As Integer

Private Sub cmdOpen_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdOpen.Click
aduHandle = OpenAduDevice(1) 'Here we get a handle to the ADU device connected via the USB port
End Sub

The Write button

Private Sub cmdWrite_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdWrite.Click
Dim iRC As Integer
Dim iBytesWritten As Integer
iRC = WriteAduDevice(aduHandle, txtCommand.Text, Len(txtCommand.Text), iBytesWritten, 500)

'txtCommand.Text is whatever data has been typed into the Data To Send text box.
End Sub 'timout is set to 500ms

The Read button

Private Sub cmdRead_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdRead.Click
Dim iRC As Integer
Dim iBytesRead As Integer
Dim sResponse As String
sResponse = "+++No Data+++"

' sresponse is preloaded to set its size and show +++No Data+++ if there is no data!
iRC = ReadAduDevice(aduHandle, sResponse, 7, iBytesRead, 500)
txtResponse.Text = sResponse 'Data is displayed in Received Data textbox.
End Sub

The Close button

Private Sub cmdClose_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdClose.Click
CloseAduDevice(aduHandle) ' Here we close the handle to the ADU device connected to the USB port
aduHandle = 0
End Sub

The Discovery Controls

The Discovery Controls are advanced functions built into the AduHid dll to obtain information about ADU devices connected to the host computer. These functions can be used to automate the selection of connected ADU devices. The Show List button causes a pop-up window to display a list of connected devices and some relevant information. The ADU Count button causes a message box to appear showing how many ADU devices are connected. The Get ADU button causes a message box to display the connected devices one at a time including their index number.

Figure 4: The Discovery Controls

Here are the subroutines for each element and a few comments.

The Show List button

Private Sub cmdShowList_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles cmdShowList.Click
Dim myAduDeviceId As ADU_DEVICE_ID
Dim iRC As Integer
iRC = ShowAduDeviceList(myAduDeviceId, "Connected ADU Devices") 'triggers the pop-up window
End Sub

The ADU Count button

Private Sub cmdADUCount_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdADUCount.Click
MsgBox("ADU Count: " & ADUCount(100)) ' count is limited to 100 devices
End Sub

The GetADU button

Private Sub cmdGetADU_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdGetADU.Click
Dim pADU As ADU_DEVICE_ID
For iAduIndex As Integer = 0 To ADUCount(100) - 1
GetADU(pADU, iAduIndex, 100)
MsgBox("Index: " & iAduIndex & " Model: " & pADU.iProductId & " Serial Number: " & pADU.sSerialNumber)
Next 'if multiple devices present, next window pops up after each is closed
End Sub

Selective Open Control

The Selective Open Control allows the handle to a specific connected ADU device to be obtained by typing the serial number into the Serial Number (s/no) to open text box and clicking the Open by s/no button. The Standard Controls can then be used to communicate with the selected ADU device.

Figure 5: Selective Open Control

Here is the subroutine.

The Open by s/no button

Private Sub cmdOpenBySNo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOpenBySNo.Click
aduHandle = OpenAduDeviceBySerialNumber(txtSNo.Text, 1)
End Sub

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