Re: [foxboro] Daily Totalizer Question

Angie,

As a first-time poster, You will quickly find out that there are as many ways 
to perform a specific function in the IA System as there are engineers making 
suggestions.  So here is only one suggestion that follows your line of 
thought ...

I doubt a single Math block will impact the Station loading, so why not set 
the Period to 1 second, then ...  If I understand your concerns with the Math 
block reading the value twice, cron will allow you to lock the Math block in 
Manual, giving it only a few second window of opportunity to read the value 
(transfer to Auto) only once daily ...  (i.e., 23:59:57 set to Auto, 23:59:59 
set to Manual).  I doubt your operators are that fast ... :-)

Joseph M. Riccardi
www.eRiccardi.com   
(440)-458-4411         Business 
(440)-725-4025         Cell

In a message dated 7/16/2002 12:42:31 PM Eastern Standard Time, 
aag43220@xxxxxxxxxxx writes:


> Subj:[foxboro] Daily Totalizer Question 
> Date:7/16/2002 12:42:31 PM Eastern Standard Time
> From:<A HREF="mailto:aag43220@xxxxxxxxxxx";>aag43220@xxxxxxxxxxx</A>
> Reply-to:<A HREF="mailto:foxboro@xxxxxxxxxxxxx";>foxboro@xxxxxxxxxxxxx</A>
> To:<A HREF="mailto:foxboro@xxxxxxxxxxxxx";>foxboro@xxxxxxxxxxxxx</A>
> Sent from the Internet 
> 
> 
> 
> 
> Hi list:
> 
> This is my first posting so bear with me.
> 
> I figured out a simple way to do this temporarily but I am looking for some 
> 
> thoughts to see if there is something.  BTW - we recently upgraded to 
> version 6.3
> 
> -----
> 
> We had/have a need to calculate a month-to-date production number utilizing 
> 
> weigh tickets from railcars.  Currently, the operator enters in the daily 
> railcar loading amount before midnight into a AIN block.  Whatever number 
> is 
> in the system before midnight is considered to be the final number for the 
> day.
> 
> To get the month-to-date number, I made a simple MATH block that checks to 
> see if the daily railcar amount (the AIN block pnt value) has changed.  If 
> it hasn't changed, it does nothing (assumes the number is the previous 
> amount).  If it has changed (assumes its a new amount for the current day), 
> 
> it adds it to the current accumulated value and stores the new number for 
> the next comparison.  I currently have the block set to a period of 8 (60 
> minutes) to give it the longest time between scans.  I have also edited 
> mastercron to reset the accumulated value at the beginning of the month 
> back 
> to 0.
> 
> It seems to be working (I have only been running it for 3 weeks now).  I 
> think it could be better.  The problem I could run into (but haven't yet) 
> is 
> if an operator incorrectly enters in the wrong number before one of the 
> hourly scans, the MATH calculates (it sees a change), the operator enters 
> in 
> the correct number after the scan time.  The block would then recalculate 
> again, only it would be too high - I don't know of a simple way to get it 
> to 
> subtract out the error other than having us DCS-folk manually fix it.
> 
> But ideally, I would like for the period to be every 24 hours -this would 
> minimize the error mentioned above because it wouldn't matter much if data 
> was entered in prior to the scan.  At the same time, though, I would like 
> to 
> keep it as simple as possible.  Perhaps some sort of script that would 
> toggle the MATH block from MANUAL to AUTO just before midnight, the block 
> would calculate (put it on a faster period when its configured so it will 
> scan while in AUTO), then toggle back to MANUAL just after midnight?  Or 
> maye something totally different?
> 
> Your feedback is much appreciated
> 
> Angie Gruber
> OxyVinyls, La Porte, TX


 
 
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