Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi Manual de usuario descargar pdf (Pagina 250)

II. SOFTWARE GUIDES - 10. Driver488/W31 10F. Visual Basic

Personal488 User’s Manual, Rev. 3.0 II-235

Establishing Communications

The following program contains most of the function calls of Driver488/W31. The user interface of

this program is intentionally simple to highlight the Driver488/W31 operations. To centralize all of the

Driver488/W31-related code, the architecture of this example is not typical of a Visual Basic program.

This example operates the multichannel, 16-bit analog to digital converter; the ADC488.

In every Visual Basic program using Driver488/W31, a file of declarations must be merged into the

program, typically to the

GLOBAL.BAS

file. In the following example, those declarations have been

omitted from the listing for the sake of brevity.

With the associated source files, the following program can be built using the file

EXAMPLE2.MAK

found on the Driver488/W31 disk.

This example has two declarations that will be used later:

Declare Function FindWindow Lib “User” (ByVal data1$, ByVal data2$)As

Integer

Declare Function SendMessage Lib “User” (ByVal winHandle%,

ByValmessage%, ByVal wp%, ByVal lp As Long) As Integer

The following declarations are included in the General section of the form, and are assumed through

the remainder of the discussion:

Dim nl As String * 2

Dim mystring As String

Dim substat As IeeeStatus

Dim adc As Integer

Dim response As String * 256

Dim intResp(500) As Integer

Dim voltage As Single

Dim sum As Single

Dim noterm As terms

Dim sample As String * 7

For the sake of this discussion, assume that Driver488/W31 has been configured to start with a

configuration including the devices

IEEE

(IEEE 488 interface) and

ADC

(ADC488/8S connected to the

IEEE 488 interface). Additional interfaces and/or devices may also have been defined, as the driver

can support up to 4 interfaces and 56 devices simultaneously. To open the two devices of interest, we

use the following statements:

If the

ADC

was not configured within Driver488/W31, it can be optionally created “on the fly”, as

shown above. First

ioError

was used to

TURNOFF

automatic error reporting so that our application

can trap the error instead. If opening the name

ADC

failed, the handle of the device

wave

, which is

‘Open Driver488/W31

ieee% = OpenName(“IEEE”)

If (ieee% = -1) Then

MsgBox “Cannot initialize IEEE system”

End

End If

‘Open device named ADC

rv% = ioError (ieee%, TURNOFF)

devhandle% = OpenName (“wave”)

adc = OpenName(“ADC”)

If (adc = -1) Then

adc = MakeDevice(devhandle%, “ADC”)

If (adc = -1) Then

MsgBox “Can not initialize device ADC”

End

End If

response = “”

rv% = GetError (1eee%, response)

rv% = BusAddress (adc, 14, -1)

1 2 ... 245 246 247 248 249 250 251 252 253 254 255 ... 399 400

Comentarios a estos manuales

Sin comentarios

Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi Manual de usuario Pagina 250

Comentarios a estos manuales

Relacionado con productos y manuales para Hardware Measurement-computing Personal488 rev.3.0 For DOS & Windows 3.Xi