//String timestamp '2023-06-16T14:10:00Z' parse to RTC_TYPE
//utc_STRING: STRING; In VAR;
//utc_RTC: RTC_TYPE; Out VAR;
//conv_WARN: BOOL; Out VAR;
//sl: INT; Local VAR;
//i: INT; Local VAR;
//step: INT; Local VAR;
//tmp_char: STRING; Local VAR;
//probe_char: STRING; Local VAR;

sl := LEN(UTC_string);
IF sl < 1 THEN //Get input str length, if blank, then skip further exec
    RETURN; 
END_IF;

probe_char := '';
step := 0;
conv_WARN := FALSE;// On each CASE step will check validity of converted value, and ret TRUE if mess up.

FOR i := 1 TO sl DO
    tmp_char := MID(UTC_string, 1, i);
    
    IF tmp_char = '0' OR tmp_char = '1' OR tmp_char = '2'
    OR tmp_char = '3' OR tmp_char = '4' OR tmp_char = '5'
    OR tmp_char = '6' OR tmp_char = '7' OR tmp_char = '8'
    OR tmp_char = '9' THEN //Check readed char digit or not
        probe_char := CONCAT(probe_char, tmp_char);
    ELSE
        IF probe_char = '' THEN 
            CONTINUE; //Keep reading if does not met any digit before, 
        END_IF;       //jump to the next char 
        
        CASE step OF //Fill RTC struct one by one, reading input string left to right
            0: utc_RTC.YEAR := TO_UINT(probe_char);     conv_WARN := conv_WARN OR (utc_RTC.YEAR < 1970) OR (utc_RTC.MONTH > 2100);
            1: utc_RTC.MONTH := TO_USINT(probe_char);   conv_WARN := conv_WARN OR (utc_RTC.MONTH < 1) OR (utc_RTC.MONTH > 12);
            2: utc_RTC.DAY := TO_USINT(probe_char);     conv_WARN := conv_WARN OR (utc_RTC.DAY < 1) OR (utc_RTC.DAY > 31);
            3: utc_RTC.HOURS := TO_USINT(probe_char);   conv_WARN := conv_WARN OR (utc_RTC.HOURS > 23);
            4: utc_RTC.MINUTES := TO_USINT(probe_char); conv_WARN := conv_WARN OR (utc_RTC.MINUTES > 59);
            5: utc_RTC.SECONDS := TO_USINT(probe_char); conv_WARN := conv_WARN OR (utc_RTC.SECONDS > 59);
        END_CASE;
        
        step := step + 1;
        probe_char := '';
    END_IF;
END_FOR;