With the version of the on-board software uploaded on 2008-05-29 at 17:58 UT, the DN values of the 3x3 array were telemetered to ground with a different pixel order compared to the standard one. The order of the 3x3 array, as telemetred by this on-board software version and subsequent ones, are recorded in the CALDB file 'phasconffile' together with their time of validity.
This task first checks if the 3x3 array telemetered is ordered according to
the standard configuration. The check is done by comparing the 3x3 pixel configuration in use at
the epoch of the observation, as stored in the CALDB file, with the standard one.
If the 3x3 pixel array is not in the standard configuration, 'xrtphascorr' re-orders the 3x3 array. The telemetered 3x3 pixel array before correction is saved unchanged in the column 'TLMPHAS' in the output unfiltered event file. The keyword 'XSTDPHAS' is added and set to 'T' to indicate that the PHAS column contains the 3x3 array in standard configuration.
> xrtphascorr infile=sw00050400062xpcw3po_uf.evt outfile=NONE