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Calendar Conflicts RRS feed

  • Question

  • We have a plan which has a base calendar (company calendar) which uses 37.5hrs per week, 08:45 to 17:00 with 45 minute lunch break (this is set up in the schedule). 

    We also have a calendar for specific resources (commissioning calendar) which has 10hrs per day, Monday to Thursday, 07:00 to 18:00 with a 1hr break for lunch. 

    We need to assign the commissioning calendar to the commissioning tasks in the plan as they were all set up on the company calendar. 

    When we assign the calendar to the tasks, non-working time is ignored and the start and finish dates are calculated on a 5 day week basis.  Work is calculated according to the standard calendar rather than the assigned calendar. 

    When the duration is increased to 10 days, the work is recalculated as 77.5hrs for task 1 and 75hrs for the remaining tasks.  If a new tasks is added which is also 10 days and the initial calendar is the 24hr calendar, work is calculated as 26.5hrs and then remains the same when the commissioning calendar is assigned.

    So, which calendar "drives" the calculations (the one set in the schedule or the one specified in the Project Information)?  Why are the results inconsistent?  What causes this disconnect?

    Regards,

    Margaret


    M.L. Pate

    Monday, April 28, 2014 3:52 PM

Answers

  • Margaret --

    I do not know where to begin because there are so many variables in your situation.  Have you done the following in this project:

    • Changed the Hours Per Day value to 7.5h and changed the Hours Per Week value to 37.5 in the Project Options dialog? You need to do that to get Duration and Work values to calculate correctly.
    • Changed the Start Date of the project to 8:45 AM?  It will default to 8:00 AM unless you manually type the 8:45 AM text after the date in the Start Date field in the Project Information dialog?

    Beyond this, your use of the Fixed Duration task type is a limiting factor on the schedule.  Because of that, assigning a the Commissioning calendar as a Task Calendar automatically throws off the schedule of your task.  The Duration value stays unchanged, but the schedule changes to account for the longer working days.

    What I would recommend you NOT do is to assign the Commissioning calendar as a Task Calendar on any task.  And then when you assign a Commissioning resource to any task, the software will calculate the Work for the task based on the schedule of the Commissioning calendar assigned to the resource.  But the software WILL NOT change the Finish date of the task automatically.  If that is the desired behavior, use a Fixed Units task type and then enter hour many hours of Work you expect the Commissioning resource to perform.

    Just a couple of thoughts.  I would gladly invite the others in our community to weigh in with their thoughts and comments as well.  Hope this helps.


    Dale A. Howard [MVP]

    • Marked as answer by mlpate64 Wednesday, April 30, 2014 11:25 AM
    Tuesday, April 29, 2014 6:32 PM
    Moderator
  • Hi Jan,

    Sorry, I found your answer a little bit confusing however Dale's second answer was a great help.  Thank you for your time anyway.

    Margaret


    M.L. Pate

    • Marked as answer by mlpate64 Friday, December 11, 2015 4:20 PM
    Wednesday, April 30, 2014 11:26 AM

All replies

  • Margaret --

    When you assign a Task Calendar to a task as an override calendar, you should also select the Scheduling Ignores Resource Calendars option as well, just to make sure that the schedule of the task is totally correct.  What the Task Calendar will do is to schedule the CURRENT amount of Work according to the new Task Calendar schedule.  So, the schedule you see for the task is now correct according to the Task Calendar schedule.

    What the Task Calendar WILL NOT do is to recalculate the Work for the task.  It will leave the Work alone.  In addition, Microsoft Project WILL NOT recalculate the Duration of the task.  This is because Duration is calculated using the formula:

    Duration = Work/(Hours Per Day x Units)

    The Hours Per Day value is specified in the Project Options dialog.  The default Hours Per Day value is 8 hours, so that is the value Microsoft Project will use to calculate the Duration of the task on which you specified the Task Calendar.

    So, I think what you are seeing is normal.  It just takes a bit of getting used to work the software works.  Hope this helps.


    Dale A. Howard [MVP]

    Monday, April 28, 2014 4:02 PM
    Moderator
  • Hi Dale,

    Thank you for your reply unfortunately it doesn't help solve the problem or answer the questions.

    The tasks are all set up as fixed duration. 

    1. If I set up a 5 day task with no task calendar and then assign a resource with the commissioning calendar, I would expect the start and finish dates to be driven by the resource calendar which has Fridays as non-working.  I would also expect the work to be calculated based on 100% assignment of the resource for the 5 day duration which gives total work of 50 hrs.  In my test plan, the start and end dates are being driven by the company calendar and the work is being driven by the value set up in the Options, ie: 37.5hrs 

    2.  If I set up a 5 day task and then assign the commissioning calendar to it, the start and finish dates are still being driven by the company calendar and the work by the Options value.  When a resource that is assigned on the company calendar is assigned to the task, the work is calculated as 30hrs - the effort is derived from the 7.5hrs per day and is assigned according to the commissioning calendar. 

    Regardless of how I set up the task, the work is always calculated on the standard 7.5hrs per day.

    Back to the problem, we have a section in the middle of the plan which needs to have the tasks on the commissioning calendar.  The tasks are currently fixed duration and on the company calendar, the resources are on the commissioning calendar.  Step by step, I do the following: -

    1. Delete the resource from the task (no work has been completed.

    2. Assign the Commissioning Calendar to the task

    3. Check the "scheduling ignores resource calendars"

    4. Re-assign the resource to the task. 

    If you do this on a task which starts on 29/04/2014 the end date should be (Tu, We, Th, Tu, We - 07/05/2014 (1st Monday in May is non-working) if it is picking up the Commissioning calendar but it is picking up the schedule from the standard calendar which means it finishes on 06/05/2014 (Tu, We, Th, Fr, Tu) which means that the duration is not being calculated from the task calendar only from the default set up in options.

    Is there a way to get it to work correctly?

    Regards,

    Margaret


    M.L. Pate

    Tuesday, April 29, 2014 12:54 PM
  • Margaret --

    I do not know where to begin because there are so many variables in your situation.  Have you done the following in this project:

    • Changed the Hours Per Day value to 7.5h and changed the Hours Per Week value to 37.5 in the Project Options dialog? You need to do that to get Duration and Work values to calculate correctly.
    • Changed the Start Date of the project to 8:45 AM?  It will default to 8:00 AM unless you manually type the 8:45 AM text after the date in the Start Date field in the Project Information dialog?

    Beyond this, your use of the Fixed Duration task type is a limiting factor on the schedule.  Because of that, assigning a the Commissioning calendar as a Task Calendar automatically throws off the schedule of your task.  The Duration value stays unchanged, but the schedule changes to account for the longer working days.

    What I would recommend you NOT do is to assign the Commissioning calendar as a Task Calendar on any task.  And then when you assign a Commissioning resource to any task, the software will calculate the Work for the task based on the schedule of the Commissioning calendar assigned to the resource.  But the software WILL NOT change the Finish date of the task automatically.  If that is the desired behavior, use a Fixed Units task type and then enter hour many hours of Work you expect the Commissioning resource to perform.

    Just a couple of thoughts.  I would gladly invite the others in our community to weigh in with their thoughts and comments as well.  Hope this helps.


    Dale A. Howard [MVP]

    • Marked as answer by mlpate64 Wednesday, April 30, 2014 11:25 AM
    Tuesday, April 29, 2014 6:32 PM
    Moderator
  • Hello Margaret,

    If you want to understand how Project works, there are two items in your second post that can stop you understanding: "I would also expect" and "to work correctly". Project has its own logic, a set of calculation rules and those will not necessarily be what you expect nor what you feel as correct.

    The major misunderstanding that IMHO causes most of your questions is the assumption that a day is an important item in Project's calculations. It is NOT. Project calculates everything in minutes (or hours if you want). Users who want can display duration or work in days, but that is just an alternative way to DISPLAY not calculate. Hereby hours are always converted into the "unusual" days unit using the hours by day conversion factor in the Options.

    Do notice that I didn't mention start, finish, nor calendar so far.

    Then there is your question which calendar drives the calculations. Talking about work and duration NO calendar even intervenes, let alone drives.

    When you say I set up a 5 day task, before all be aware that Project has recorded a 37,5 hours task (I understand the HPD parameter is 7,5 hrs per day). That is what you enter, and what you do further on does not change that. A fulltime resource on that task will have 37,5 hours of work. Did I mention a calendar so far? No I did not.

    Now let's suppose you assign a 10hrs/day calendar to the task. 37,5 hrs of work will now take (as difference between start and finish) 3,75 "real" days. That is where at last the calendar comes in - to define working time and thus scheduling finish vs. start. It cannot, repaet not, change duration (as expressed in hours) nor Work.

    Does this clarify a bit?


    Tuesday, April 29, 2014 8:09 PM
    Moderator
  • That's fantastic thank you. 

    M.L. Pate

    Wednesday, April 30, 2014 11:25 AM
  • Hi Jan,

    Sorry, I found your answer a little bit confusing however Dale's second answer was a great help.  Thank you for your time anyway.

    Margaret


    M.L. Pate

    • Marked as answer by mlpate64 Friday, December 11, 2015 4:20 PM
    Wednesday, April 30, 2014 11:26 AM
  • Margaret --

    You are more than welcome for the help, my friend!  :)


    Dale A. Howard [MVP]

    Wednesday, April 30, 2014 11:38 AM
    Moderator