Identifier     make_detmask

 Purpose        make a detector mask out of the det and band switches

 Synopsis       detmask = make_detmask(band, det, struc, detoffset, stat)

 Arguments      Name        I/O  Type      Description
                -----------------------------------------------------
                band         I   scalar/   Detector band(s) to which operation
                                 intarr    shall be limited (SWS specific)
                det          I   scalar/   Detector(s) to which operation
                                 intarr    shall be limited
                struc        I   struct    input spectrum
                detoffset    I   int       offset for detector counting
                                           (LWS: 0-9, SWS: 1-52)
                stat         O   int       error stat, 0 if ok, 1 if fatal
                                           error occured
                
 Returns        detmask = intarr(52), a detector mask indicating the choosen
                detectors. 
                0 if fatal error occured

 Description    If no band or det are given then all elements of detmask are
                set to 1. If det and/or band are given, they are checked for
                a valid range and the corresponding indices in detmask are set
                to 1. If det and band are conflicting a warning is issued.

 Comment        detmask is intarr(52) even in case of LWS. This slight
                'overkill' saves some case distinctions.

 Example        detmask = make_detmask(band, det, in1, det1offset, stat)

 Dependencies   CALLS: sap_error, sap_keyword_set
                CALLED FROM: arithm

 Category       ISAP

 Filename       make_detmask.pro

 Author         E. Sturm (--> ES)
                A. Fiedler (--> AF)

 Version        1.0

 History        0.1   14-09-95  ES  (based on D. Lutz's routine)   
                0.2   27-09-95  AF  modified bandind and check for valid
                                    detector range
                1.0   30-11-95  ES  V1 delivery
                1.1   29-02-96  ES  error stat added
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Copyright (C) 1995, Max-Planck-Institut fuer extraterrestrische Physik (MPE);
                    Garching, Germany                                       ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;