In Microsoft Project scheduling takes place in one direction only. When you create a project, you decide whether the system is to schedule from the project start date or the project finish date. If you choose scheduling from the start, all tasks are initially scheduled to start as soon as possible. If you schedule from the finish, all tasks are scheduled to start as late as possible. You can add constraints to a task in Microsoft Project either manually or automatically.
1. To add constraints manually, call up the detail screen for the task and go to the Advanced tab page.
2. In the Constraint Task section, enter the type of constraint and the date. The following types of constraint are available in Microsoft Project:
Ў Start no earlier than
Ў Start no later than
Ў Finish no earlier than
Ў Finish no later than
Ў Must start on
Ў Must finish on
Ў As late as possible
Ў As soon as possible
The last two options are not strictly constraints. Depending on whether you are scheduling from the start or the finish, the default value is either As soon as possible or As late as possible.
If, for example, you change the value from As soon as possible to As late as possible the task is scheduled to finish as late as possible within the period of the summary task. In this case, successor tasks are taken into account. This is one way of moving dates in OpenPS4MSP from earliest set of dates to latest or vice-versa.
3. Choose OK.
If you move a task by dragging it in the diagram area or by entering a date, Microsoft Project automatically sets a constraint for the task. If the project is scheduled from the start, it sets a Start no earlier than constraint. If the project is scheduled from the finish, the system sets a Finish no later than constraint.
Work and duration are defined in Microsoft Project in the same way as in the Project System. Work is the amount of effort, measured in time units, put into a task by a resource. The duration is the amount of time between the start and finish of the task. Resources are the people, equipment, office space, and so on, for carrying out a task. On the resource sheet, you define the resource (see Entering Resources for a Task) specifying how many units are available at this resource.
In Microsoft Project duration, work, and resources are mutually dependent:
· Duration = Work/Resources
On the Advanced tab page you specify which of these three parameters is to be kept constant in the Task type field. The program uses the settings from the calendar and other options to convert units.
You have created a task that has a duration of 10 days and assigned a resource to this task with one unit. In the project options you have specified a 5 day week with an 8 hour working day. The system then calculates the work to be 80 hrs. If you then change the duration to 12 days, the following happens:
§ If the task has a fixed duration, the work increases to 96 hrs (12x8), and the resources remain at one unit.
§ If the task has fixed work, the work remains at 80 hrs but only 0.83 units resources are required.
§ If the task has fixed units, the units required remain one and the work increases to 96 hrs
Since the number of resources is not transferred to the Project System, use tasks with fixed work if you want to change the duration and with fixed duration if you want to change the work.