Tutorial > Visual basic6.0

Visual Basic6.0

Communicate with the PIA4800 series using VISA through GPIB, RS232C or USB.

Setting the "Project"

At first, set the communication driver (VISA liabrary) for the "Project".


Click "Project" on the menu bar, then select "Add Reference" to refer "VISA COM 3.0 Type Library".


Communication through GPIB, RS232C or USB

After setting the communication driver, it enables to communicate by GPIB, RS232C or USB.

The following describes the communication procedure for via VISA.

Open the VISA

To communicate with the device of GPIB, RS232C or USB via VISA, it requires to open the VISA first. When opening the VISA, specify the I/O resource.


Example : To open VISA by using USB

Set rm = CreateObject("VISA.GlobalRM")

Set msg = rm.Open("USB::0x0B3E::0x1014::00000001::INSTR", NO_LOCK, 0, "")


"USB::0x0B3E::0x1014::00000001::INSTR" is the I/O resource.

The I/O resource is specified by the following constructions. The part indicated with [ ] can be abbreviated. Enter the appropriate value in the part specified in oblique characters.



Example : The primary address 3 of the measurering instrument connected to GPIB0.




Example : The measurering instrument connected to the serial port COM1.




Example : The USNTMC measurering instrument having with the vendor ID (VID)2878, Product ID(PID)4116 and serial number "00000001".



For VISA, the alias can be used for the I/O resource.

When using the alias for the I/O resource, even the alias name to be hard coating directly in the application, it can be easily converted to the appropriate I/O resource name.


Example : When using the alias (MYPIA) for the I/O resource.

Set msg = rm.Open("MYPIA", NO_LOCK, 0, "")


When the alias is used, the actual I/O resource is specified by such an external configuration table.

 When using the USB (example for KI-VISA)


In case of using VISA other than KI-VISA, please refer to the applied VISA manual.


Controlling the devices

Next, using such a "Read", "Write" to control the devices.



   msg.WriteString ("NODE 5")      'Specify a node address.
msg.WriteString ("CH 1")        'Specify Channel 1.
msg.WriteString ("VSET 10.0")   'Set 10V.
msg.WriteString ("ISET 1.0")    'Set 1A.
msg.WriteString ("OUT 1")       'Output ON. 

Closing the VISA.

Close the VISA at the end.

A command for "Open" and "Close" of the VISA is required only once in the program.



Sample program for controlling the PWR400L by the PIA4850

Option Explicit

Dim rm As VisaComLib.ResourceManager

Dim msg As VisaComLib.IMessage


Private Sub cmdRead_Click()

   'Display the voltage and current values measured on PWR400L in the text box.

   Dim iPSno As Integer

   Dim strBuff As String


   msg.WriteString ("TRM 2")                              'Set the terminator to EOI.


   msg.WriteString ("NODE 5")                             'Specify a node address.

   msg.WriteString ("VOUT?")                              'Specify a measured voltage value.

   strBuff = msg.ReadString(256)                          'Read from PIA.

   txtVolt.Text = strBuff                                 'Display the voltage value in the text box.


   msg.WriteString ("IOUT?")                              'Specify a measured current value.

   strBuff = msg.ReadString(256)                          'Read from PIA.

   txtCurr.Text = strBuff                                 'Display the current value in the text box.

End Sub


Private Sub cmdSet_Click()


   msg.WriteString ("NODE 5")                             'Specify a node address.

   msg.WriteString ("VSET 5")                             'Set 5V.

   msg.WriteString ("ISET 3")                             'Set 3A.

   msg.WriteString ("OUT 1")                              'Turn ON PWR output.

End Sub


Private Sub Form_Load()                                   'Open the VISA

   'Device configuration

   ' <<Controller>>

   '      PIA4850

   ' <<Power supply>>

   '      PWR400L



   Set rm = CreateObject("VISA.GlobalRM")

   'Set msg = rm.Open("GPIB0::1::INSTR", NO_LOCK, 0, "")

   Set msg = rm.Open("USB::0x0B3E::0x1014::00000001::INSTR", NO_LOCK, 0, "")


End Sub


Private Sub Form_Unload(Cancel As Integer)                 'Close the VISA


End Sub