Preventive maintenance actions can be generated according to certain conditions of an equipment object. In order to control preventive maintenance actions in this way, you should define appropriate parameters for the object. Next, you decide which of the parameters are to be used as criteria for generating PM actions. Finally, you take and register measurements for those parameters.
There are two types of parameters: cumulative and limit values. When a measurement of a parameter falls outside the specified limit values, or the cumulative value exceeds the limit for generation, a PM action is generated. One example of a parameter with limit values is temperature; a cumulative parameter could be operating time.
See the chain of events for condition-based PM in the figure below.
The chain of events for condition-based PM actions.