Verify the names of the columns in your data files by running the ftool flcol on a sample file. In the case of a Standard-2 file, you'll get:
Name of FITS file and [ext#][] standard2.fits
___Column_Names_________Formats______Dims______Units___
Time D s
X1LSpecPcu0 129I (129) count
X1RSpecPcu0 129I (129) count
X2LSpecPcu0 129I (129) count
X2RSpecPcu0 129I (129) count
X3LSpecPcu0 129I (129) count
X3RSpecPcu0 129I (129) count
X1LSpecPcu1 129I (129) count
X1RSpecPcu1 129I (129) count
X2LSpecPcu1 129I (129) count
X2RSpecPcu1 129I (129) count
X3LSpecPcu1 129I (129) count
X3RSpecPcu1 129I (129) count
. . . .
. . . .
. . . .
Standard-2 is the only science array configuration that offers full PCU and anode ID. The column X1LSpecPcu0, for example, corresponds to the left anode of the first (top) layer of PCU0. By contrast, Standard-1 only provides PCU ID. Its columns have names like XeCntPcu0.
Decide from which PCU, layers or anodes you want to extract data.
Create an ASCII file listing the columns you want. One name per line, ending with a carriage return. For example, the list of Standard-2 columns
X1LSpecPcu0
X1RSpecPcu0
X1LSpecPcu1
X1RSpecPcu1
X1LSpecPcu2
X1RSpecPcu2
corresponds to the top-layer of PCU0-2
Enter the name of the column list, prefaced with an @-sign at the saextrct prompt
Name of COLUMNS to be accumulated