A preventive maintenance (PM) hierarchy is a group of PMs with parent-child relationships. Use a PM hierarchy to schedule a group of work orders for an asset hierarchy or a location hierarchy.
PM hierarchies generate an organized group of work orders for an asset or location hierarchy. Work is typically organized this way for inspections and large projects. If any PM in the hierarchy is due, it triggers a generation of work orders for the entire hierarchy.
At the highest level of a PM hierarchy, there is one parent PM. This top-level PM can have one or more child PMs. Each child PM can have one or more child PMs, and so on. A child PM can only have one parent PM.
You can add a sequence number to each PM in a PM hierarchy. The sequence number gives workers an indication of the order in which to perform the work. The sequence number is copied to the work orders that are generated from the PM. However, there is no validation on this number; duplicates and null values are allowed.
You can also generate simple work order hierarchies by applying a route to a PM.
You cannot delete a PM that is part of a hierarchy. You must remove it from the hierarchy before you can delete the PM.