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non-breaking tasks

8 replies [Last post]
Thu, 2010-08-19 09:05
John Banks
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How do I set a task to be non-breaking? In other words, on 5 day week, a non-breaking task would not start on a Thursday, but rather the next Monday?
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Thu, 2010-08-19 13:32
#1
Rafael Davila
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John,

You can use Lag Calendars if your software provides you with the ability to define individual Lag Calendars, if not then you can use a Milestone to get similar results.

Lag Calendar

My most frequent use of Lag Calendars is when in need to define it to be based on calendar days while the activities calendars are not on workdays, and perhaps different calendar each activity.

Beware that many institutions are isolated into what is available in their countries, so do not take for granted everything they write. The AACE International Recommended Practice No. 49R-06 is an example of an erroneous and misleading statement; they wrongly say “currently only Deltek’s Open Plan™ CPM software allows for the assignment of different work calendars to individual relationships.” , just open your eyes.

Best Regards,
Rafael
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Thu, 2010-08-19 16:27
#2
Rafael Davila
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Start on Mondays using Dummies

Although not an MS Project regular user I tried my suggestion using milestones but it seems computations in MS Project differ. However managed to get the same results in a similar way I did using Lag Calendars. I created a special week to work one hour from 1am to 2am on Monday, Tuesday and Wednesday and used a dummy intermediate activity with duration of one hour using this calendar.

I understood you want to allow your activities to start Monday, Tuesday or Wednesday but not Thursday nor Friday. You can download the sample MS Project job from the following link.

http://rapidshare.com/files/413951262/Start_on_Mondays.mpp.html

Sorry for any inconvenience, not an expert on MS Project.

Best Regards,
Rafael
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Fri, 2010-08-20 01:33
#3
John Banks
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Rafael

Thanks for your thoughts on this - I don’t think I made the query clear - I have some operations which must be completed in one continuous action but only a 24/5 shop-floor calendar. Consequently these activities can start on any shift as long as they complete by the end of Friday back shift (week starts Sunday nightshift)and donot have a duration beyond 5 days (which tends not to be an issue).
We couldn’t find a solution within the software, so are now trialling a macro.
Thanks again
John
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Fri, 2010-08-20 10:28
#4
Rafael Davila
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John,

I can see your issues are with modeling of shifts, that you do not know what work will be done on each shift as it depends on where it starts. I believe MS Project as well as Primavera P6 cannot model shift work if you do not know in advance what work will be done on each shift. Spider Project can handle the issue with ease as shown in the following illustration.

Non Breaking Tasks

The logic for the start of the activities can be modeled as I proposed because you know the total duration of the activities string, your model can be done easily with Spider Project as I understand it now, but still have some doubt a macro or some script will do it within MS Project. Sorry I tried to do my best but this is as far as I can go with MS Project.

Adding productivity differences among shifts would be interesting as no longer the total duration of the string can be pre-determined. Also Shift spanning two days shall be no problem on any software is just a matter of assigning work hours early am and late pm to the same day as needed.

Good Luck,
Rafael
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Fri, 2010-08-20 23:50
#5
Rodel Marasigan
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John,
There is a way to set a continuous 5day work without breaking the task. You can set a task working from Monday to Friday only by using a trigger milestone having a trigger calendar and linked to normal activity.

First create a calendar having special working day (i.e. 5:00PM - 12: AM Sunday only) and assign it to your milestone. These milestones will only placed on Sunday night work. Then link this milestone as predecessor for non breaking task and a successor of normal activity.
Ex: Normal Act-> FS -> Trigger Milestone ->FS-> Non-Breaking Task
See sample below:
NBTask

If the non breaking task can start from Sunday night to Tuesday night then set the trigger milestone calendar from Sunday night to Tuesday night and it will be placed on that specified date followed by non breaking task.

Best Regards,
Rodel
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Sat, 2010-08-21 02:14
#6
Vladimir Liberzon
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Hi Rodel,
your solution is not good.

Just imagine that nonbreaking activity has two days duration and preceding activity finishes on Monday. With your solution an activity will be delayed until next Sunday without proper reason.

In Spider Project you can just set that an activity is nonbreaking (we call it continious but maybe it makes sense to rename) and that’s all.

NBT

In the example above all activities are "continious" and Friday and Saturday are non-working days.

Best Regards,
Vladimir
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Sat, 2010-08-21 07:56
#7
Rodel Marasigan
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Hi Vladimir,
I understand that Spider Project has an option of continuous activities which allow the activity to work continuously on a day and start on the following day for the next activity but Microsoft Project don’t have that options. Also my understanding is a continuous activity is link to normal activity and not all continuous activity. As I mention on my post the trigger milestone can have a calendar setting for non working day (i.e Thu, Fri & Sat) so it can only placed on Sun to Wed therefore if continuous activities have only 2 to 3 days work still possible but for 5 days continuous work then set a calendar as per my example.
I also understand that some version of MSP ignore calendar for 0 duration so I suggest to put 0.01 day on milestones to respect calendar setting.

Best Regards,
Rodel
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Sat, 2010-08-21 11:05
#8
Vladimir Liberzon
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Hi Rodel,
I know that MS Project and Primavera do not model continious performance but your solution will cause unnecessary delays. It does not matter if preceding activities are non-breaking or normal. In any case if activity will finish before Friday it can start, if not - it shall be delayed.
Where to put your trigger milestone if non-breaking activity has two days duration and you don’t know before scheduling when the preceding activities will finish?
Preceding activity may finish on Monday and on Thursday. If on Monday - no delays, if on Thursday - start on the next week. After scheduling you don’t need milestones - just study the schedule, set Start No Earlier Than constraints (or dates to your trigger milestones) and reschedule. And repeat this process many times until all activities will be scheduled properly.
I am afraid that it is too hard.

Best Regards,
Vladimir
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