About nested PMs

Nested planned maintenance (nested PMs) are a scheduled maintenance feature that allow you to manage repeating tasks that can be completed together, but at different intervals. 

For example, an asset may have three tasks: task A is performed every 500 kilometres, task B every 1000 kilometres, and task C every 2000 kilometres. Instead of creating separate scheduled maintenance for each repeating task, you can manage all of them on one record with nested PMs. 

This article includes the following:

• Feature overview
• Example

Feature overview

You can view and edit nested PMs in the Nested PMs tab on a scheduled maintenance record:

As shown above, nested PMs have a code, a parent, and a multiplier (aside from the PM with the greatest frequency):

• Codes (N1, N2, etc.) are automatically assigned based on the order of creation. For example, the first PM created on the scheduled maintenance record is N1, the second is N2, and so on. 
• Multipliers are set by the user and determine the time or meter reading interval of each maintenance procedure. The most frequent PM (N1) has no multiplier. 
  For example, giving a PM a multiplier of 2 means that the interval will be twice as long as its parent's. If its parent's interval is 6 months, then the PM in question has an interval of 6 × 2 = 12 months. In other words, it would be performed yearly. 
• Parents are any pre-existing nested PM that the PM uses to calculate its own interval. When creating a new nested PM, you select which PM to use as a parent. Any nested PM can be a parent; however, N1 PMs can only be a parent, and never a child. 

The Next Iteration Cycle section displays the PMs that are set to be completed next.

After you've created your nested PMs, they can be assigned to any tasks on the scheduled maintenance record to determine their frequency. Using the example above, a work order is generated weekly for N1 tasks. However, any N2 tasks will only appear on every fourth work order, since they occur on a monthly frequency.

To learn more, see Create a time-based nested PM and Create a meter-based nested PM.

Example

A machine could require the following service:

• Oil change every 500 hours
• Filter change every 1000 hours
• Motor shaft alignment every 3000 hours

At 500 hours, only an oil change is needed, but at 1000 hours, both an oil and filter change is needed, and at 3000 hours, all three maintenance procedures need to be performed. The nested PMs for these maintenance procedures might look like the following: