Gas Flow Totalization

I am having the gas flow in MMSCFD on one of the analog input channel, and i want to totalize the flow on 24 hours basis in MMSCF.
I am thinking of using TOT instruction in Rslogix5000 platform (although never used this before). My problem is, this instruction totalize the value and compare it with the target value. In my case i donot have any target value to compare with. So what i was thinking of doing is to use a timer that will trigger after every 24 hrs and at the same time start the tot instruction and when the timer done bit is done , i copy the old total value into a temp register and initiate a reset command to TOT instruction. Since i have never used this instruction before, thats why i want to have a second opinion on what i plan on doing?

The TOT instruction has the time base in days, minutes etc, i use the days which means it will take a value say x, from 4-20 ma signal and do the following:

x mmscfd * (DeltaT/2*86400), where as delta T will be the scan time of my program or task inwhich the routine is residing.

Is there anyother thing i need to set or configure in this instruction? or Alternatively, is there any other way of achieving this goal? Thanks in advance

Regards

There is a PREV.. (previous) tag associated with this block. When you set the clear bit to the block it moves the current total to the previous tag. We have done this with CLGX and many totalizers. The direction you are heading will work.