Something

c     ***Read the file and execute minor adjustments***
      read(UNIT=15, FMT=*, IOSTAT=EOF) TIME, TEMP, PRES, VOL
10      if(EOF .GE. 0) THEN
          COUNT=COUNT+1
          
c     ***Change to military time and add appropraite time stamp***
      TEST = .TRUE.
        if(TIME .GE. 1200) TEST = .FALSE.
        if(TIME .GE. 1300) TIME=TIME-1200
        if(test) then
         goto 20
        else
          TCH='pm'
          endif