CompuScope SDK for L.. - Egmont Instruments

GageDeepAcquisition.viGageDeepAcquisition.vi is the Main VI for large acquisitions from a single CompuScopesystem. The definition of large varies with System configuration but is roughly of order16 MegaBytes. For small acquisitions, LabVIEW is fully capable of downloading theentire acquisition into PC RAM. For larger sizes, the host PC will begin to use “virtualRAM”, which is a section of the hard drive that Windows treats like PC RAM. Usage ofvirtual RAM causes the hard drive to spin and slows down execution. For large enoughdata sets, LabVIEW will simply refuse to download the data at all.In order to avoid trying to keep large data sets in LabVIEW at one time,GageDeepAcquisition.vi manages deep acquisitions by dividing them up into moremanageable data pages. The VI does initialization, configuration setting and acquisitionsas usual. After the acquisition, however, only a single data page of the acquisition isdownloaded and displayed.After doing the acquisition, the VI goes into a loop that allows the user to select anddisplay any page from the large acquisition. There is a control/indicator pair that shows“Page XX of YY”, where XX is the value in the adjustable Page control. YY is the totalnumber of Pages that is equal to (Length/Page Size). With each change of Page controlvalue, the VI downloads and displays a new page, so that only one page is resident in theVI at a time. The adjustable Page Size default is 32768. The time x-axis is offset toindicate the page position in time. For example, if the user displays Page 11 of a capturetaken at 100 MS/s, the lower x-axis limit would be 10 X 32k / 100 MS/s = 326.78milliseconds.20 CompuScope SDK for LabVIEW for Windows