Activity Start Date

Amit,

I like your approach to use a finish date in Primavera P6 so the software will calculate the remaining duration, it solves the fractional days issue always, good for calendar week with different hours work days. Reminds me of SureTrak "expected finish constraint" that in reality is not considered a constraint but a remaining duration calculator.

Arun,

The milestone procedure can be easily adapted to model start of an activity to happen only on certain days of the weeks, say Monday or Tuesday. For all activities considering all link types the milestone procedure and the links calendar it is too complicated to be of practical use, it is more a curiosity. I hope eventually software developers figure it out on a practical way because the need is real.

At times we have the constraint for activities to start at any AM hour only as PM it is too late to make sense, at times it is the contrary some activities are scheduled to start PM only.

Seems we got another reason why deterministic CPM schedules are optimistic. In a critical tandem/chain many half days can add significant "unexpected" delay.

Best regards,

Rafael

Hi Arun,

What exctly do you mean by Time Period calculation? This error usually comes due to 2 reasons :

1) When we put a constraint and the constraint starts/ends at a different time than the calendar time

2) When you update your activity and update the % complete to get your Finish Date. You might end up putting a number like 10.2% or 10.6% and Primavera calculates the percentage to the last decimal and finishes the activity on different time than calendar end time.

To avoid the above problem directly put a finish date on your started activity and Primavera will automatically calculate the % complete and Remaining Duration. It is a much easier and accurate way of getting % Complete (Only if you are using Task Dependent activities)

Regards

Amit

Check out my blog on Primavera at http://www.primaverablog.in

Dear Arun,

Goto Edit>User Preferences>Dates>Time>Choose 24 hours. Then goto the Predecessor activity and check the Finish Date & Time on the activity. The FInish Time should be equal to the Finish time of your Calendar. If it is not thats why the successor is Starting on the same day. This could be due to the following reasons :

1) The predecessor of the activity has Actual FInish before the end time of Calendar (Change it to Finish time and Re-schedule and it will be fine)

2) Their is a finish or start constraint and they are After or Before calendar Start Time or FInish Time

Fixing these time will fix your problem.

Regards

Amit

Check out my blog on Primavera at http://www.primaverablog.in

If you are working on software that uses hour as the planning unit the following are 3 ways I can suggest for dealing with this issue.

1. Avoid use fractional days in your durations as to mimic day as your planning unit, the way P3 allowed, this can be very tricky with lag calendars when predefined by a global rule. You might get fractional remaining duration "days" when using % for updating your jobs, watch for this issue if you choose this method.

2. Use a special calendar for the link that will drive early start of the successor activity along with the successor calendar. For links with lag use double links with nominal successor negative lag. This is easy to do in software that allow for individual links calendars and double links, but harder if not impossible when link calendar is predetermined by a global rule that you can set only within some limits ( P3 falls in the global rule category, not sure about newer versions of P6 ). Do not confuse double links with multiple links even if between same nodes, it is different functionality. If a predecessor SF or FF link can drive the activity then it gets even more complicated.

3. Use a special calendar for an intermediate milestone that will drive early start of the successor milestone activity and this in turn will drive successor activity along with the successor calendar. This will add a lot of milestones but perhaps this is your only option on software limited at handling link calendars.

I use a combination of no 1, and no 2 on SS and FS links only on chains where activities have fractional days on their calendar work week.; does not add the additional milestone for every such activity. I recognize the ideal would be 100% no 2 so nothing is manual and the model logic takes due care, but for SF or FF links it gets too complicated for practical use, not to mention double links.

I believe from the above you can adapt a combination of no 1 and no 3 and still be on a practical approach if option no 2 is not available to you.

Dear arun, 

I faced similar situations, checl the calender u will get it write.

could you have a negative -1 lag? please check

P6 makes basic calculation based on hours , so it is common to have your problem in schedules

Solution to your case now as you already prepare the schedule

To add lag to FS Relation so the activity will start while after predecessor – next day ( NOT BEST SOLUTION)

Another better solution is – follow below

• Check first activity start date ( should be first our of activity calendar)
• Check project / activity calendar ( how many hours per day)
• If possible make all activity calendar as default calendar  

Dear Arun,

You have to check the time period when the first activity has finished .may be the 1st activity has finished earlier then the finish time of the day.

i mean if you have assigned your calendar timing till 6PM  and your 1st activity has finished at 4pm then the next activity will start immediatly.

so it is always better to show the hour period in the dates column to get a better idea.

Cheers