This depends upon which VIs you are using. Are you using a driver specifically for the 2620A, the 488.2 VIs, or the VISA VIs? It also depends upon how the instrument returns data. You could use the array VIs in LabVIEW to parse the string and put it into an array, but first we'll need to know how it is sent back. For instance, it is long values separated by commas, etc. Let us know how the string is configured and we'll find a way to do it.
J.R. Allen