ROUTINE SUMMER
  ALIAS
    SUMMER_START_MONTH = PARAMETER[35]; %Mån sommar start
    SUMMER_END_MONTH = PARAMETER[36]; %Mån sommart slut
    SUMMER_START_DAY = PARAMETER[37]; %Dag i månad som sommar startar
    SUMMER_END_DAY   = PARAMETER[38]; %Dag i månad som sommar slutar
    SUMMER = CHANNEL[137]; %Kanal 137
  VAR
  BEGIN
    IF SUMMER_START_MONTH > SUMMER_END_MONTH THEN
      % error, always summer
      SUMMER <- 1;
    ELSE
      IF ((((TIME_MONTH = SUMMER_START_MONTH) AND (TIME_DAY >= SUMMER_START_DAY)) OR (TIME_MONTH > SUMMER_START_MONTH)) AND (((TIME_MONTH = SUMMER_END_MONTH) AND (TIME_DAY < SUMMER_END_DAY)) OR (TIME_MONTH < SUMMER_END_MONTH))) THEN
        SUMMER <- 1;
      ELSE
        SUMMER <- 0;
      ENDIF;
    ENDIF;
END;