storing highest and lowest values

PLC is a SLC 5/04

I can one write logic to see how high or how low a value got?

Example their is a 0-10v scaled signal coming into my analog input
card the signal is fluctuating way to fast for me to use the values in my code. I know that you can use a first order filter to filter the value but that is not what im trying to do. Im trying to write logic to see how high the value reached or how low that value reached, that way I can incorporate deadbands from the high and low values that I get to control other parts of my logic

Use a timer, when timer ticks first time saves incoming value to a known place A, next time timer ticks compare incoming value to value saved in A, if incoming value is less than value in A do nothing if greater than A then moved that value to A. This way A contains the max value. Do the same but opposite for min value, in this case use a new register call it B.

The easiest way I think would be to do a simple compare then move.

For instance:

Les (Your Value), (Tag 1) ------ Mov (Your Value), (Tag 1)

So everytime the value you are looking as gets lower than tag 1 it stores it in that tag. You might want to set up some limits so you dont go faulting the processor though.

Setup two registers. One, labled 'Highest' will be preset with the LOWEST possible value (zero maybe?). The other, labled 'Lowest', will be preset with the highest possible value.

On each pass through the program:

If Current < Lowest then set Lowest = Current
If Current > Highest then set Highest = Current

When finished your test period you will ahve your answers.

Thanks for the feedback guys I'll try these out tomorrow