VHA Property

Syntax

CWIMAQ.VHA

Data Type

Boolean

Purpose

Status of Variable Height Acquisition (VHA) on the device.

Remarks

You can use VHA trigger mode with line scan cameras to allow a continuous acquisition of images that vary in height. The height of the acquisition is based on the width of a pulse on a signal I/O line. To specify which signal line to use in VHA mode, add a signal object to the CWIMAQSignals collection and configure it for cwimaqCaptureEveryImage. Acquisition begins on the assertion of this signal line and terminates when the line is deasserted or the number of lines equals the height of the image that is set using Measurement and Automation Explorer (MAX).

Example

' This example requires you to have the following controls on the form.
' 1) A button named Acquire.
' 2) A button named Stop.
Private Sub Acquire_Click()
    ' Enable VHA mode.
    CWIMAQ1.VHA = True
    ' Set the RTSI line 0 to be the signal line that
    ' specifies the height during acquisition.
    CWIMAQ1.Signals.Add.Name = "RTSI0"
    CWIMAQ1.Signals("RTSI0").Initialize cwimaqRTSI, _
                                        cwimaqCaptureEveryImage, _
                                        cwimaqActiveHigh, _
                                        0
    CWIMAQ1.AcquisitionType = cwimaqAcquisitionContinuous
    CWIMAQViewer1.Attach CWIMAQ1.Images(1)
    CWIMAQ1.Start
End Sub

Private Sub Stop_Click()
    CWIMAQ1.Stop
End Sub

See Also

CWIMAQSignals

CWIMAQSignal