Parts per Minute Display

jthornton

Member
Join Date
Jul 2002
Location
Poplar Bluff, MO
Posts
295
I have one customer that i programmed a parts per minute display. I used without much thought on my part the "number of parts per time period" method. Count the number of parts in 10 seconds multiply by 6 and there you go. Not! the machine if it has one more or one less the display jumps by enough to concern the customer. Ok If I use a longer time period that will smooth it out but the delay in speed changes will be slow.... If I use time per number of parts I feel that I will be in the same boat... Is there a slick way to do a running average that will not jump around alot?

TIA
John
 
I use a timer with a time base of .01 sec and then divide this into 6000. This gives me a realtime parts/min.

Example:

If T4:0.acc = 200
6000/200 = 30 parts/min.
 
Averaging

Maybe if you store the parts per minute every 5 seconds or so in a 20 integer fifo and then average... or any variation on this theme to give the customer the desired responsiveness/smoothness.
 
Sorry about that.

The timer is tracking the time between parts.

Back to my example:
200 time units/part
100 time units = 1 sec.
(200 time units/parts)/(100 time units/1 sec) = 2 sec/part
60 sec. = 1 min.
Now
(60 sec/1 min.)/(2 sec./part) = 30 parts/min
Instead of doing two computations I multiplied my
(60 sec.*100 time units) = 6000 since these are both constants

Hope this helps
 

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