Preventive maintenance actions can be generated according to certain conditions of an 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. When two or more cumulative measurements are registered, it generates a condition based forecast PM plan. If several measurements are entered for a parameter that may result in an unrealistic forecast plan compared with the start value and interval on the PM action, there is a mechanism to prevent generating more than one maintenance plan line on the same planned date.
See the chain of events for condition-based PM in the figure below.
The chain of events for condition-based PM actions.