24 hr highest temp reading, need comments

I am using a A?B 5/04 with RSLogix 500 and I am trying to come up with a way to display the highest temp from one thermocouple in a 24 hour period.

I came up with the following and even though I hit the verify button with no errors it just doesn't seem right to me.

What do you think?

Thank you.

Better photo

Here is a bigger font size.

if temp>highest temp_buffer
then highest_temp_buffer:=temp;
end_if;

if 24_hour_done then
highest_temp:=highest_temp_buffer;
highest_temp_buffer:= 0
end_if;

...

This is how I have done it in an S7 300.

I would probably do it like this, however this doesn't provide a Rolling 24h, it simply resets after a fixed 24h period. It'd be best to have a rolling one, which would mean you'd have to store the highest value recorded over short periods (say an hour) and then compare the 24 highest recorded values over a 24 hour period to obtain the highest to display. Then start the loop again, overwriting the first value. I'd probably examine the clock on the PLC and whilst it's equal to a particular hour, do the above and at the end of the hour (when it changes to the next) store the value and compare the last 24 hours worth of stored values.

Here's a 24h Rolling version, had to attach in two pictures. I haven't tested it, but I think its right

(Ive only done the first 3 hours, but as it's repetative it should be easy for you to add the rest. The pointer is already set for 24 hours)