Re: [foxboro] Running Hours Counter

Dirk,
    I'm interested to know if the PI totalizer function you mention is 
in OSI PI's standard library as a configurable tag or if you had to 
create a special tag function with your own totalizing algorithm?  If it 
is a standard PI function can you send any information you have about it? 
    This is a common issue and my experience has been that the PI 
administrators wanted the DCS to run an accumulator and pass the 
totalized value to a standard PI tag.  This is not the best solution due to:

- potential over-runs in the CP that can make the Accumulator value 
inaccurate
- the accumulator gets reset during a CP reboot
- the people using the accumulated data don't have access to the DCS 
reset function
- the accumulation of this type of data is not really a control function 
and shouldn't bog down the control system or the people that support 
it.  They should focus on process control.

Your PI solution is ideal because it puts the information into the hands 
of the users that need those functions and lets them decide how to use 
it and reset it if needed.  They can also set up the email notifications 
that make sure the correct person gets alerted when a threshold 
condition occurs.  I have had requests in the past to provide equipment 
hour meters on the DCS and even to generate DCS alarms when thresholds 
are met but have resisted doing it for the reasons listed above. 
    My viewpoint is that each discipline needs a system to use as a 
primary work interface.  The Control System is the primary work 
interface for the Operations department to operate the plant/refinery.  
The Control System should be supported, configured and maintained by a 
dedicated and specialized group. Although it is great thing that the 
data generated in the control system can be passed to an information 
system such as OSI PI, care should be taken to insure that the control 
system doesn't get bogged down trying to generate all of the process 
information needed by other disciplines such as maintenance, 
engineering, environmental, etc.  PI is an excellent and flexible tool 
that can be used to combine and process that information and is 
available to all disciplines throughout a corporation.  The control 
system is not the place to do all of that.  This topic would be a good 
one for a "White Paper".  Does anyone know of one that already exists?

Cheers,
Tom VandeWater
Control Conversions Inc.
Kapolei, HI  USA


dirk.pauwels@xxxxxxxxxx wrote:
> We use PI from OSI as an historian, in PI we can create totalizer tags
> which  accumulate running hours for pumps, motors etc....We use it in an
> excel sheet where the tags are shown along with the running hours
> converted. We compare the amount of hours to a set maintenance interval to
> know which pumps,motors are due for maintenance or overhaul. We also have
> the possibility to send an automated email to the maintenance coordinator
> to inform him which items are due for maintenance. He can set the
> maintenance intervals and reset the total running hours when the servicing
> has been done. Nice asset....
> We do not use the accumulator blocks for this, cause our maintenance guys
> prefer to use PI. (they have no acces to the DCS displays)
>
> Buying OSI software for this would be overkill off course but maybe you
> already have some kind of historian which allows you to gather these
> running hours.
>
> Besides running hours we also intend to install temp reading and frequency
> sensors on our important pumps to allow maintenance to track their
> condition. When PI shows a gradually increase in temp or freq outside the
> normal amount, maint. knows the pump will need some inspection. Depending
> on the freq and the make and type of the pump you can also determine which
> part of the pump needs servicing. Nice thing about it is that maint would
> not need to do manual checks anymore (which are timeconsuming and often not
> done at all). they're notified automatically whenever a pump exceeds the
> temp or freq limits. We will be testing this on a couple of blowers soon.
>
>
> Rgds,
>
> Dirk Pauwels
>
>
> wrote:
>
> You could also add the values to the Historian so if the latest value
> is lost, you at least know what it was and can put it back in (that
> would be a pain for many values, although it could be scripted of
> course)
>
>
>
>
>
>  
>  
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