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Planview Customer Success Center

Task Constraint Types

Changing the Constraint Type on the tasks can control the Start or Target Date of a task. Constraints can be flexible, semi-flexible or inflexible depending on the type of constraint chosen. Flexible constraints work with dependencies to schedule the task to occur as soon or as late as possible. Some constraints give you the ability to specify that the task needs to start or finish before a chosen date. These dependencies still can affect the task schedule. Inflexible constraints take priority over dependencies restricting the task to start or finish on a specified date.

The default Constraint Type is As Soon As Possible (ASAP).  

When you enter a Start or Target Date for a task, this indicates that you do not want the task to start or finish earlier than that date. Entering a Start Date will change the task Constraint Type to Start No Earlier Than (SNET).  Similarly, entering a Target Date will change the task Constraint Type to Finish No Earlier Than (FNET).  

Entering durations and dependencies will give you the most scheduling flexibility. Entering semi-flexible or inflexible constraints by changing Start Date, Target Date or Constraint Date should only be used if you have unavoidable constraints.  In this case, you may want to make the task a manually scheduled task.

You can create and modify the constraints on your tasks with following types:

Constraint Type

Acronym

Description

Scheduling Impact

As Soon As Possible

ASAP

With this constraint, Project schedules the task as early as it can, given other scheduling parameters. No additional date restrictions are put on the task. This is the default constraint for newly created tasks in projects scheduled from the start date.

Flexible

As Late As Possible

ALAP

With this constraint, Project schedules the task as late as it can, given other scheduling parameters. No additional date restrictions are put on the task.

Flexible

Finish No Later Than

FNLT

This constraint indicates the latest possible date that you want this task to be completed. It can be scheduled to finish on or before the specified date. A predecessor won't be able to push a successor task with an FNLT constraint past the constraint date. For projects scheduled from the finish date, this constraint is applied when you enter a finish date for a task.

Moderately Flexible

Start No Later Than

SNLT

This constraint indicates the latest possible date that you want this task to begin. The task can be scheduled to start on or before the specified date. A predecessor won't be able to push a successor task with an SNLT constraint past the constraint date. For projects scheduled from the finish date, this constraint is applied when you enter a start date for a task.

Moderately Flexible

Finish No Earlier Than

FNET

This constraint indicates the earliest possible date that you want this task to be completed. The task cannot be scheduled to finish any time before the specified date. For projects scheduled from the start date, this constraint is applied when you enter a finish date for a task.

Moderately Flexible

Start No Earlier Than

SNET

This constraint indicates the earliest possible date that you want this task to begin. The task cannot be scheduled to start any time before the specified date. For projects scheduled from the start date, this constraint is applied when you enter a start date for a task.

Moderately Flexible

Must Start On

MSO

This constraint indicates the exact date on which a task must be scheduled to begin. Other scheduling parameters such as task dependencies and lead or lag time can't affect scheduling the task unless this requirement is met.

Inflexible

Must Finish On

MFO

This constraint indicates the exact date on which a task must be scheduled to be completed. Other scheduling parameters such as task dependencies and lead or lag time can't affect scheduling the task unless this requirement is met.

Inflexible

 

If you choose As Soon As Possible (ASAP) or As Late As Possible (ALAP), a Constraint Date is not required. These constraints are flexible. The tasks will be scheduled using dependencies and the Schedule From date.