FIFO with 10 sec delay

RsLogix 500... micrologix 1500

how can I make something similar to a first in first out register for floats (maybe integers)with a 10 second delay?

I want to collect numbers from a process in approx 1/2 - 1 sec intervals, use them at another point in the process 10 sec later.... and then evaporate them. Additionally I want to hold the timing if the process stops.

thanks in advance

Just trigger your FIFO queue every 10 secs, the instruction for that are FFL (load) and FFu(unload), FIFO size depends on your requirements.

Interval=0.5 seconds and the length of file = 10 seconds, so you need at least 20 elements in your file.

Let's double that, in case you need to double the frequency to 1/4 second sample rate. So, let's use F8:0 through F8:39 for the samples.

Now write code to enable your repeating sample interval timer. Any enabling logic, followed by a not done condition for ther timer, and then the TON instruction with a 1/2 second preset.

After that, you need a rung to take samples when the timer is done. So, youll examine the timer done bit, and when true, you will COP F8:1 to F8:0 with a length of 39, and add a branch to move the new sample to F8:39.

So, F8:39 will be the newest sample, and F8:38 will be what was there one preset (1/2 a second) ago, and F8:19 will be what was sampled ten seconds ago.

Note that if you change the preset, you need to change the offset to match (or calulate and limit check the result to use indirection).