In order to perform preventive maintenance, you need to define PM actions. For a PM action you should at a minimum, enter information such as object ID, action and maintenance organization.
In order for the PM actions to generate work orders on a regular basis (calendar-based generation), or based on the condition of the object (condition-based generation), or because of a certain type of event that has occurred (event based generation), you need to enter one or several generation criteria on the PM action. You can define one generation criteria, or combine several generation criteria on one PM.
To generate work orders for due PM actions, the Calendar generation, Event generation and Condition generation jobs need to be run on a regular basis (you decide how often). You can also generate work orders manually for a specific PM action.
Calendar-based generation
For PM actions that should generate work orders on a regular basis you would use calendar criteria to define when to start generating work orders, and how often.
When you define the calendar criteria you have several alternatives to specify start date, interval, and unit of measure. The alternatives and possible combinations are shown in the table below.
Start Unit | Start Value | Interval Unit | Interval | Explanation |
Day | 08-Aug-2019 | Day | 1 | 1 day later |
Day | 08-Aug-2019 | Week | 1 | 7 days later |
Day | 08-Aug-2019 | Month | 1 | Next month, the same date |
Day | 08-Aug-2019 | Year | 1 | Next year, the same date |
Week | 1932 | Week | 1 | Next week, Monday |
Week | 1932 | Year | 1 | Next year, same week, Monday |
Month | 1908 | Month | 1 | Next month, first available date |
Month | 1908 | Year | 1 | Next year, first available date |
Combinations of calendar-based PM supported by the system.
When the calendar criteria is defined, a PM Plan is automatically created. The length of the PM plan is determined by either the PM_PLAN_HORIZON system parameter (defined in IFS/Application Services) or the valid dates entered on individual PM actions. The PM_PLAN_HORIZON is common for all calendar based PM actions, regardless of whether a valid date is entered for the PM actions. The valid dates serve as a method to limit (or to cap) the longevity of individual PM actions.
Example of calendar-based generation.
You can generate work orders for calendar-based maintenance as often, and as far ahead in time as you wish. Longer planning time allows you to analyze resource requirements early and coordinate maintenance with other activities. By connecting Generated Work Time Calendars (defined in IFS/Application Services) to PM actions, you can make sure that the planned date of the PM actions generated will always be on a working day. For example, the figure above illustrates a monthly calendar-based generation where the planned date of each PM action falls on the first of each month. In reality the first of each month does not always fall on a working day. Assume that 980501 falls on a Saturday. If a calendar is connected, the planned date for the generated PM action will be moved to the closest working day which in this case would be 980503 (Monday).
Event-based generation
If you want to generate work orders based on a certain type of event you can use the event-based generation criteria. An event can be an occasional event like for example a breakdown, but can also be a recurring event like a monthly or a yearly shutdown etc.
For an event you have the possibility to to add one or more event date periods that depending on status will appear as event lines in the maintenance plans for relevant PM actions and also be available for event generation into work orders and work tasks.
Available statuses for an event date period are shown in the table below.
Status | Explanation |
Preliminary | This is the status the event period gets at creation. |
Planned | In Planned status the event date period will appear as an event line in the maintenance plans. |
Active | When status is changed to Active the event lines for the date period in the maintenance plans will become available for event generation. If used the PM action will now start to be scheduled in IFS Planning & Scheduling Optimization (PSO). The dates for the event date period will still allow to be changed. |
Completed | After the status has been changed to completed the event period is seen as finished. This status is an end status and it is not possible to re-open a completed event. |
Cancelled | In this status the event period is cancelled without having been carried out. This status is an end status and it is not possible to re-open a cancelled event. When an event date period is set to cancelled, the event lines for this date period in the maintenance plans will be removed. |
Notice that when an active event date period has been generated into work orders and work tasks, the event date period line will still remain in status Active. By that there will be a manual step to change an event date period from status Active into status Completed.
Condition-based generation
In situations where you wish that a certain condition of the equipment object should determine when work orders should be generated, you can use condition-based criteria. For example, you can use a condition-based PM so that a work order is generated to inspect a machine if the machine's measured temperature rises above 100 degrees. Or a work order is generated to lubricate a machine when it has run for 40 hours.
In order to create a condition-based PM action, a parameter must have been defined and connected to the object id. A parameter can measure one of two types of values; Accumulated or Limit values. An accumulated parameter can for example be 'Operation time' or 'Produced quantity'. A limit parameter can be 'Temperature', 'Oil level', 'Pressure', 'Water flow', etc.
If any cumulative criteria is registered, a criteria line is shown on the Maintenance Plan tab even before any measurement is registered. You can manually generate work orders having this line only. When two or more accumulated measurements are registered, it generates a condition based forecast PM plan by calculating the average use per day under the assumption of linear use of the equipment object.
IMPORTANT: Upon registering accumulated measurements, the condition based forecast PM plan will be regenerated accordingly. The user can choose to run the regeneration as a background job by setting the system parameter PM_CON_PLAN_SYNC to BATCH. The Plan Out of Sync flag in the PM Action/Condition tab will indicate if the condition based forecast PM plan is in conflict with the latest measurement entered for the object. When the condition based forecast PM plan is in conflict, it will not be allowed to generate Work Orders from the affected PM Action. If the parameter PM_CON_PLAN_SYNC is set to ONLINE, the regenerate plan process will run immediately, and this might take a few minutes.
On the PM action you define what values are outside what is acceptable for the object's parameter. When a measurement is recorded against an object parameter, and the measurement value falls outside the acceptable values defined on the PM action, a work order will be generated when the condition generation is run.
The process of defining a parameter and PM action, recording measurement and generate work order is described in the picture below.
The chain of events for condition-based PM actions.