Steve
Mon Mar 17 17:10:50 CDT 2008
If a "day" is defined as any 8-hour segment, a task that starts Monday at
8am and run continuously until Tuesday 8am will show "3 days" as the
duration in the Gantt chart task table even though in our normal world we
would say it's only 1 day. 24 hours / 8 hours per duration-day = 3
duration-days. Duration time is only loosely related to time as indicated
on the clock on the wall or tracked by conventional calendars such as your
day-planner. Think Star-Trek - the Enterprise used an Earth-standard day to
record time that bore no relation at all to the rotational period of the
planet they were visiting. In Project a 'standard-day' is defined as every
X working minutes, X being defined by the setting in Tools/Options/Calendar.
In your example, because work is proceeding 24/7, the number of working time
minutes between Monday 8am and Friday 12 noon IS the same as the number of
working time minutes in 12.5 standard 8-hour workdays, thus in duration days
the duration of that task is 12.5 days, not 4.25 even though the bar on the
graphic only covers four days + out of the week. There are 12.5 8-hour
segments between start and end, thus it is 12.5 days duration.
--
Steve House [Project MVP]
MS Project Trainer & Consultant
Visit
http://project.mvps.org/faqs.htm for the FAQs
"Mike" <Mike@discussions.microsoft.com> wrote in message
news:748A778C-30D9-4432-9340-48FBAAFFC7D9@microsoft.com...
> Thanks for replying, Steve.
>
> I believe what you're saying should produce the duration I'm expecting,
> i.e.
> 100h, or 6000 minutes, of Work broken up into (3) 8-hour (480-minute)
> segments per day (as you've described) would result in a duration of just
> over 4 days. Why am I seeing 12.5 days?
>
> I must not be seeing the whole picture...
>
> --
>
> -Mike
>
>
> "Steve House" wrote:
>
>> It's not that Project can't use multiple calendars - it does so very
>> nicely.
>> The confusion arises when one forgets that duration is ALWAYS actually
>> measured and calculated in units of working time minutes to the nearest
>> 10th. In order to use more convenient units of days, weeks, months, etc,
>> they have to be converted to and from minutes. The conversion factors
>> applied are global within a project and independent of the working time
>> calendar. With the default hours per day setting of 8
>> (Tools/Options/Calendar) ANY time period of 480 minutes is considered a
>> "day." The calendars, OTOH, determine WHICH minutes out of the 24-hour
>> sunrise to sunrise day are to be considered working time. We enter a
>> task
>> with a duration of 3 days, ie, 1440 working time minutes, starting Monday
>> @
>> 8am. If the calendar governing that task is the standard 8-hour default
>> calendar, those 3 480-minute "days" run 0800-1700 Mon, 0800-1700 Tue, and
>> 0800-1700 Wed. On the other hand, if the 24-hour calendar is governing
>> that
>> task, those same 3 480-minute "days" run 0800-1600 Mon, 1600 Mon-0000
>> Tue,
>> 0000-0800 Tue. If the task is assigned to a resource who works
>> part-time,
>> having a calendar that shows his hours of work as 8am to 12 noon Mon thru
>> Fri, the same 3-day (1440 working time minute) task will start Mon 0800
>> and
>> end the following Monday at 12 noon, 7.5 actual elapsed ordinary
>> wall-calendar days later, each elapsed calendar day Mon through Fri only
>> 'burning up' 240 working time minutes, thus requiring 2 sunrise-sunset
>> days
>> to equal 1 working "day."
>>
>> HTH
>> --
>> Steve House [Project MVP]
>> MS Project Trainer & Consultant
>> Visit
http://project.mvps.org/faqs.htm for the FAQs
>>
>>
>> "Mike" <Mike@discussions.microsoft.com> wrote in message
>> news:C45B12C6-6026-44AD-AC6B-CCF968B24E88@microsoft.com...
>> > Thanks for replying, Glen.
>> >
>> > We have a mix of resources where some of our equipment is run over a 24
>> > hour
>> > period, but the people and other equipment will be utilized within the
>> > standard 8 hours workday.
>> >
>> > If project can't handle the use of multiple calendars, then why does it
>> > know
>> > that the duration is 4 days when displaying the Gantt chart bars?
>> > Project's
>> > inability to handle multiple calendars comes as a shock and
>> > disappointment
>> > in
>> > what I would consider a pretty common scenario.
>> >
>> > Approaching the problem another way, if the calendar options were set
>> > so
>> > that "Hours per day" were 24 hours rather than the default 8 hours,
>> > would
>> > Project schedule tasks properly since working time of the
>> > 8-hour-per-day
>> > resources were restricted by their Standard calendars?
>> >
>> > --
>> >
>> > -Mike
>> >
>> >
>> > "Mike Glen" wrote:
>> >
>> >> Hi Mike,
>> >>
>> >> Welcome to this Microsoft Project newsgroup :)
>> >>
>> >> If all your work is on a 24 hour basis then you should change the
>> >> working
>> >> hours: see FAQ Item: 5. Default Working Hours. However, I suspect
>> >> this
>> >> is a
>> >> one-off and Project cannot handle effectively different calendars - it
>> >> has
>> >> to pick one to show - the standard project calendar based on an 8-hour
>> >> day
>> >> as you discovered. Don't forget that although the Duration shows 12.5
>> >> days,
>> >> the Work is correct at 100 hours. You'll have to live with that.
>> >>
>> >> FAQs, companion products and other useful Project information can be
>> >> seen
>> >> at
>> >> this web address:
http://project.mvps.org/faqs.htm
>> >> Hope this helps - please let us know how you get on :)
>> >>
>> >> Mike Glen
>> >> MS Project MVP
>> >> See
http://tinyurl.com/2xbhc for Project Tutorials
>> >>
>> >>
>> >>
>> >> "Mike" <Mike@discussions.microsoft.com> wrote in message
>> >> news:82BD227C-A4F7-40C8-9867-4422C73B588B@microsoft.com...
>> >> >I have a Fixed Work task that will take 100 hours of Work. The
>> >> >resource
>> >> >is
>> >> >a
>> >> > piece of equipment that is allocated at 100% Units on the 24 Hours
>> >> > Base
>> >> > Calendar.
>> >> >
>> >> > The Duration, however, is calculated at 12.5 days in the Task view,
>> >> > which
>> >> > is
>> >> > what you'd expect for the Standard Base Calendar (8 hours/day). The
>> >> > Duration
>> >> > should be just over 4 days for this resource at 24 hours/day, which
>> >> > is
>> >> > how
>> >> > it
>> >> > appears in the Gantt chart (blue bar extends over a four day
>> >> > period).
>> >> >
>> >> > What could be causing this? Thanks.
>> >> >
>> >> >
>> >> > --
>> >> >
>> >> > -Mike
>> >>
>> >>
>> >>
>>
>>