Measurement Computing Data Acquisition Systems rev.10.4 - Manual (Page 21)

Daq device errors will send the program into the error handling routine. This is the error handler. Program
control is sent here on error.
ErrorHandler:
errorString$ = "ERROR in ADC1"
errorString$ = errorString$ & Chr(10) & "BASIC Error :" + Str$(Err)
If Err = 100 Then errorString$ = errorString$ & Chr(10) & "DaqBook Error
: " + Hex$(daqErrno&)
MsgBox errorString$, , "Error!"
End Sub
One-Step Command Acquisitions
This section shows the use of several one-step analog
input routines. These commands are easier to use than
low-level commands but are less flexible in regard to
scan configuration. These commands provide a single
function call to configure and acquire analog input data.
This example demonstrates the use of the 4 Daq device’s
one-step ADC functions. Functions used include:
•
VBdaqAdcRd&(handle&,chan&, sample%,
gain&)
•
VBdaqAdcRdN&(handle&,chan&, Buf%(),
count&, trigger%, level%, freq!,
gain&,flags&)
•
VBdaqAdcRdScan&(handle&,startChan&,
endChan&, Buf%(), gain&, flags&)
•
VBdaqAdcRdScanN&(handle&,startChan&
, endChan&, Buf%(), count&,
triggerSource&, level%, freq!,
gain&, flags&)
This program will initialize the Daq device hardware,
then take readings from the analog input channels in the
base unit (not the expansion cards). For transporting data
in and out of the Daq device driver, arrays are
dimensioned.
Dim sample%(1), buf%(80), handle&,
ret&, flags&, gain&
The following code assumes that the Daq device has been successfully opened and the handle& value is a
valid handle to the device. All the following one-step functions define the channel scan groups to be
analog unipolar input channels. Specifying this configuration uses the
DafAnalog and the DafUnipolar
values in the flags parameter. The flags parameter is a bit-mask field in which each bit specifies the
characteristics of the channel(s) specified. In this case, the DafAnalog and the DafUnipolar values are
added together to form the appropriate bit mask for the specified flags parameter.
The next line requests 1 reading from 1 channel with a gain of ×1. The variable DgainX1& is actually a
defined constant from DaqX.bas, included at the beginning of this program.
Note: DafSigned does not work in conjunction with DaqBook/100.
ret& = VBdaqAdcRd&(handle& 0, sample%(0), DgainX1&,
DafAnalog&+DafUnipolar&+DafSigned&)
Print Format$“& ####”; “Result of AdcRd:”; sample%(0)
The next line requests 10 readings from channel 0 at a gain of ×1, using immediate triggering at 1 kHz.
ret& = VBdaqAdcRdN&(handle&,0, buf%(), 10, DatsImmediate&, 0, 1000!,
DgainX1&, DafAnalog&+DafUnipolar&)
Print “Results of AdcRdN: ”;
For x& = 0 To 9
Print Format$ “#### ”; buf%(x&);
Next x&
Programmer’s Manual 988594 API Programming, General Models 2-11