Preventive Maintenance Overview
The Plant Maintenance module in SAP R/3 provides a very powerful, although somewhat complex, method of planning and organizing work to be performed on a regular schedule, when specific performance triggers have been reached, or a combination of the two.
Without launching into a detailed discussion regarding maintenance planning, a subject to which many books has already been dedicated, some description is necessary. In simple terms, reactive maintenance occurs when an event occurs that requires maintenance to be performed on a machine. Preventive maintenance attempts to minimize reactive maintenance by scheduling preventive maintenance work to be performed on a regular schedule. Preventive maintenance, however, may not be entirely cost effective, since some maintenance may be performed more often than is necessary. Predictive maintenance attempts to address that concern through analysis of the preventive maintenance and refining the preventive maintenance schedule in such a way that the preventive maintenance is performed at an optimal time. Of course, such maintenance concepts are more involved and more complex than described, but cannot be discussed more completely here.
SAP R/3 Plant Maintenance provides work order cycles for reactive (breakdown) maintenance and preventive maintenance, as well as providing analysis tools to assist with predictive maintenance. The primary advantage of preventive maintenance work orders is that they can be produced by the system automatically. The actual work order cycle is discussed later. Discussion of the configuration for Preventive Maintenance in the Implementation Guide (IMG) will follow this section.
Maintenance Task Lists
Some of the terminology involved with SAP’s maintenance planning mayrequire some familiarization. A task list is required to provide a step-by-stepinstruction of the maintenance to be performed. In SAP’s terminology, thetasks of a task list can be equated to the operations of a work order. When awork order is created from a maintenance plan, the tasks of the related task list become operations of the resulting work order. Each task on the task listmay include labor requirements and material requirements.
A maintenance strategy consists of maintenance cycles usually grouped by a unit of measure common denominator. For example, a “Monthly” strategymay consist of cycles such as “Every month, ” “Every 2 months, ” “Every 4months, ” “Every 6 months, ” and so on. The common denominator is one month.
A maintenance package, or simply package, is simply one of the cycles in a strategy. The example above of a maintenance strategy shows that the “Monthly” strategy includes the packages 1 month, 2 months, 4 months, and 6 months.
A strategy (MNTH) and some of its packages (cycles).
In recent releases, SAP has attempted to make maintenance planning a little more simple where possible. A result of this is that the maintenance item isnow less obtrusive than before. In instances where maintenance is to be performed on one piece of equipment and for only a single cycle, the user maybe unaware that a maintenance item is involved, since its creation is automatic.A maintenance item serves to link the maintenance tasks and cycles toone or more pieces of equipment (or other technical object).
The maintenance plan combines all of the previously mentioned terms intoan overall plan. The maintenance plan itself simply provides a start date forthe cycle(s) contained within, as well as some other default settings. Several maintenance items may be contained in the same maintenance plan if thestart date of the required packages (cycles) can be the same.Creating and Maintaining Maintenance Plans The basic steps for creating a maintenance plan are as follows:
Starting a Maintenance Plan (Scheduling)
Once the previous steps have been accomplished to create the maintenanceplan, the plan must be assigned a start date (a proposed start datemay have been entered during the creation or during the saving of themaintenance plan) and then must actually be started.
The term initial start is sometimes used to indicate the first time amaintenance plan is started. This is accomplished by simply clicking on a button marked “Start” on the “Schedule MaintenancePlan” screen, providing a date on which the plan will start, andthen saving. The “Schedule Maintenance Plan” screen,which shows the “Start” button. Although the “Scheduling Parameters” tab is available here for viewing, the scheduling parameters should have been set prior to scheduling the plan, sincethose parameters will affect the scheduling of the plan.
Note that the “Start” date does not indicate the date on whichthe first work order will be produced or released, but it doesindicate the date from which all the packages (cycles) in the plan will be started. For example, if the strategy is weekly and one ofthe packages applied to a task is once per week, the first work order will be due one week after the start date of the plan. Thework order may be created before the due date, depending onthe scheduling parameters in the plan and/or the strategy.
The “Schedule Maintenance Plan” screen before scheduling.
Start In Cycle
If a convenient date to start the plan does not coincide with thelogical start of a maintenance cycle for a piece of equipment,there is an option for the maintenance plan to start in cycle. Inorder to start a maintenance plan somewhere in its cycle, theprocedure is much the same as the initial start, but with the addition of an offset. The offset indicates the amount of timeinto the cycle that the plan should be started.
Maintaining Maintenance Calls
In order to “skip” a call, which means that scheduled work willnot be performed, the specific call to be skipped must beselected on the “scheduled calls” list and the “Skip call” buttonnear the bottom of the screen must be clicked. Skipping a callmay not cause the next call to be rescheduled. If the next callmust be moved forward, it may be necessary to release the subsequentcall manually.
Releasing Calls Manually
If it becomes necessary to release a call before its scheduled releasedate, a call can be manually release by selecting the call and clickingon the “Release call” button near the bottom of the screen.Manual calls can be viewed from this screen via the “Manual calls”tab.
Deadline Monitoring, formerly known as “Date Monitoring, ”may be used to produce one or many preventive maintenanceorders at once. The terms “Deadline Monitoring” and “DateMonitoring” are both misleading in that the functionality doesnot simply monitor calls and work orders. If not carefully used,Deadline Monitoring can produce and possibly release many work orders by mistake.Taking scheduling and control parameters into consideration, ifcalls are due within the number of days specified in DeadlineMonitoring, a work order will be created for each call duewithin that time period.If security has not been implemented beyond the transactioncode level, it is possible to produce work orders for another planner group or even another plant intentionally or by mistake.
If implementing SAP R/3 Plant Maintenance for more than oneplanner group or for more than one plant, security at the appropriate levels is strongly recommended. Deadline Monitoring is often used to group preventive maintenance calls and orders and is run on a regular basis, quite often as aregularly scheduled process, or “batch job.” It prevents the necessityof updating the scheduling of maintenance plans manually.
Work orders created must be released before any actual goodsissues or time (labor) confirmations can be charged to them. If work orders are not configured to release upon creation, it maybe necessary to release work orders manually, including thosecreated by Deadline Monitoring.
Back to the Implementation Guide (IMG)—Maintenance Plans
The step-by-step discussion of the Plant Maintenance Maintenance Plans section of the implementation guide is continued below:
Maintain Authorizations for Planning
Maintaining authorizations, a security function of the SAP R/3system, is best done in co-operation with the individual(s) whose responsibility it is to maintain security for the system. See the section“Security: Authorizations and Roles” for more information.
Define Plant Sections
This setting is typically used to represent individuals responsiblefor certain areas of a plant based on production responsibility. The intent is that, should a problem occur in a certain area ofthe plant, the person responsible can be determined and notified. This IMG entry is a duplicate of entries in the “Technical Objects” and “Maintenance and Service Processing” areas.
Define Maintenance Planner Groups
This setting is also a duplicate of settings in the “TechnicalObjects” and “Maintenance and Service Processing” areas. Amaintenance planner group may be composed of one or morepeople who have the responsibility for planning maintenancework. A maintenance planner group that has been defined for apiece of equipment, for example, will by default appear on workorders related to that piece of equipment.
Define ABC Indicators
One more duplicate of settings in the “Technical Objects” and“Maintenance and Service Processing” areas, The ABCIndicator field can be used as a means of categorizing equipment.There is no definite use for the field, but it is typically used to represent the importance or criticality of a technicalobject. Although the values A, B and C are provided by default,more may be added or any may be deleted as required.
Set Maintenance Plan Categories
There is an entry in this configuration step for PlantMaintenance work orders to be generated from maintenanceplans, among other default settings. SAP R/3 versions from 4.5onward also allow the creation of notifications from maintenanceplans. By default, the PM maintenance plan category willspecify that a PM maintenance plan will generate a maintenancework order. This can be changed here, if necessary.
Define Number Ranges for Maintenance Plans
This setting can be used to define a separate number range foreach of the previously mentioned maintenance plan categories,if desired. The maintenance plans created in each maintenanceplan category can be automatically or manually assigned a numberfrom the same number range or from different numberranges based on the settings made here. See the section titled“Number Ranges” for more information. Ensure that the numberrange is large enough to permit the assignment of numbersto maintenance plans into the foreseeable future.
Define Number Ranges for Maintenance Items
Maintenance items, simply stated, provide a means of assigningmaintenance task lists to multiple objects based on the same schedulingstart date. At least one maintenance item is created for eachmaintenance plan, so the number range available for maintenanceitems should never be smaller than the number range provided formaintenance plans. If there is even a small chance that multiple maintenance items will be assigned to a maintenance plan, thenumber range for maintenance items should be larger than that formaintenance plans to allow for the assignment of numbers tomaintenance items into the foreseeable future.
Define Sort Fields for Maintenance Plan
Here, methods of sorting and grouping maintenance plans may bedefined. The main advantage to providing sort fields for maintenanceplans is to allow scheduling of multiple plans as a group inorder to save time. The alternative may be to perform the scheduling individually. Some thought may be required to provide someconvention or standard naming for the sort field values.
Define Field Selection for Maintenance Plan
When a list of maintenance plans is displayed, the settings heredetermine which maintenance plan fields are displayed, and inwhich order. As with other settings discussed previously, thefield identified as #1 will be displayed first, on the left side of thescreen displaying the list of maintenance plans. The field identifiedas #2 will be displayed immediately to the right of field #1and so on. The numbers, as discussed previously, do not specifya position on the screen, just the order in which each field is displayed from the left.
Define Field Selection for Operation Data
As in the above setting, when a list of operations in the scheduling overview is displayed, this setting determines which fields are displayed by default, and in which order. Unless a specificfield is checked as “invisible, ” the user can still select whichfields to display on the scheduling overview. These settings primarily control the default display.
Set List Editing
The next several configuration settings allow the control and defaults of selection criteria for the display of lists of maintenanceplan and maintenance item data. Similar to “set list editing”steps discussed previously, these settings can be saved as analternative to the default setting or in most cases can be saved asthe default setting.
A work center, from an SAP Plant Maintenance perspective, is usuallyone or more people. If a work center is comprised of more than one person,those people should be equally qualified. That is, it doesn’t matter which person is assigned to perform a task. In this way, several peoplewith equal qualifications can be grouped together and their combined capacity can be used to more effectively schedule work.
Work centers are assigned to cost centers, from where valid activities andactivity rates are derived. This is the source of planned and actual laborrates, multiplied by the number of hours, for example, that provides thecost of labor required to perform a task.
It is important to note that in the Production Planning module of SAP R/3,a work center is normally used to specify a place where work is performed,or to specify a machine that performs the work. In the Plant Maintenance module, a work center can also identify one or more similar machines thatare used to perform maintenance work. This can serve as an alternative to defining the machine as a PRT (Production Resources and Tools).However, a Plant Maintenance work center most often defines a person ora group of people.
To determine whether the Plant Maintenance work center can define agroup of people, first determine if it matters which of the people in the group is assigned to perform a particular task. If only a particular person in the group can perform the task, it is likely that the person does not belong to the work center. For a group of people to belong to the same work center, it usually should not matter which of the people in the group is assigned to a particular task.
They should all be capable of performing similar tasks and they should allbe charged at the same labor rate to the work order, where applicable.When configuring work centers, particularly the “Configure ScreenSequence for Work Center” step, remember that not all of the work center functionality and screens are relevant to Plant Maintenance. Forexample, if the “Technical Data” screen is active for Plant Maintenance and some of its fields are required, this may cause problems for the personcreating a Plant Maintenance work center. The person may find themselves on the “Technical Data” tab, which is difficult to exit without losing data if the required information is not available, which it may notbe for Plant Maintenance.
After the appropriate screen sequence has been defined, be sure to goback to the step described next, “Define Work Center Types and Link toTask List Application.” This ensures that the proper field selection and screen sequences are assigned to the appropriate work center category.
When defining a work center (outside of the Implementation Guide), besure to enter data on the Capacity Header screen and its subscreens, if applicable, to ensure that the proper capacity has been defined for thework center. Otherwise, assigning the work center to work orders will cause a warning message stating that not enough resources are available to perform the work. The Capacity Header screen can be accessed byclicking on the “Capacity” button near the bottom of the screen on the“Capacities” tab when creating or changing a work center. From the Capacity Header screen, the “Intervals and Shifts” button can beused to create a variety, or rotation, of shifts for the work center, if required.
The “Change Work Center Capacity Header” screen.
A description of the Implementation Guide configuration steps for workcenters follows:
Define Work Center Types and Link to Task List Application
One primary function of this configuration step is to set thefields and screen sequences that are available when creatingwork centers. The Plant Maintenance work center category maydefault to the field selection and screen sequence for machines.
Changing the field selection and screen sequence settings relevantto Plant Maintenance will help to present screens that betterrepresent Plant Maintenance work center requirements. Whether the work center can be used in other applications may also be controlled here.
Define Field Selection
This setting can be used to control whether fields relevant towork centers are input fields, display only fields, mandatory input fields, and so on. The field attributes can also be setaccording to the value of specific influencing field values. For example, if the work order category is specific to Plant Maintenance, some fields may be hidden. This allows the fields to be available for other work center applications, such asProduction, while being hidden for Plant Maintenance use.
There is often no need to make changes to this configuration setting for Plant Maintenance. The parameters defined here areused in the subsequent configuration step, Define Standard ValueKeys. This setting, along with the subsequent setting allow for standard setup and teardown times, which are often more appropriate for Production work centers than Plant Maintenance work centers.
Define Standard Value Keys
More often than not, the standard value key used for Plant Maintenance purposes is SAP0, which includes no parameters from the previous configuration step. If a standard setup, teardown,or other standard value is to be considered in scheduling, a different standard value key, along with one or more parameters from the previous configuration step, may be used.
Define Employees Responsible for Work Centers
Define a person or group responsible for the maintenance of work center master data for each plant. If an individual is identified, rather than a group, it may be beneficial to use a code, role, or position to represent the individual. Using an individual’sreal name will require maintenance of this setting when the individual’s role changes.
Create Default Work Center
A default work center may be useful in order to reduce the amount of time required to create multiple work centers. Prior to creating one or more default work centers, it may be even more beneficial to create a default capacity, which can provide further default information to the default work center. Creatinga default capacity, if desired, can be found in the Implementation Guide (IMG) by following the menu path Production → Basic Data → Work Center → CapacityPlanning →Define Default Capacity.
Define Task List Usage Keys
This configuration step can be used to control the types of tasklists where a work center may be used. The default settings aremost often acceptable. A common work around when configurationof task list usage 004 (Only maintenance task lists) is not adequate is to refer to task list usage 009 (All task list types)when creating a work center. If task list usage 009 is used, however,the work center may be used in task lists in which it mightbe inappropriate.
Maintain Control Keys
There are several settings in this configuration step that control whether tasks related to the control key are relevant for scheduling,costing, capacity requirements, printing, confirmation, andso on. There are several default control keys relevant to PlantMaintenance. These begin with “PM” and in many cases maybe adequate. Add others, if necessary, but take care not to alteror delete other control keys that may already be in use, or maybe used in the future, by other SAP modules. When the system is in use, the control key in Plant Maintenance is assigned to eachoperation of a work order or task list.
One or more qualifications may be defined here for later use to determine whether a person is suitable or qualified to perform atask. This setting is specific to each plant.
Configure Screen Sequence for Work Center
There are several screens involved in the definition of a workcenter. This setting controls the order in which the screens arepresented as well as whether the screens are presented at all and whether data entry on any given screen is mandatory. If achange to this setting does not appear to work properly, it maybe worth checking to see that the previous configuration step,Define Work Center Types and Link to Task List Application, is configured to the correct field selection and screen sequences.
Maintain Task List Status
For most basic uses of task lists in the Plant Maintenance module,the task list statuses provided as defaults are sufficient. For Plant Maintenance purposes, only two of the default statuses arerequired, 1 (Created) and 2 (released for order). Do not delete the other entries unless they will never be used by any other module, such as Production Planning. If there is a specific reasonto create any additional statuses, they may be added here. Inusing the system, however, when searching for task lists, the system requires that a task list have the status of “2” to be found.Task lists with any other status cannot be found with the standard list display functionality.
Define Task List Usage
In most cases, particularly for Plant Maintenance purposes, theSAP provided defaults are acceptable here.
Configure Planner Group
Individuals or groups responsible for task list planning are identified here. This is not necessarily the same as planner groupsfound in other sections of the IMG. A setting made in one planner group configuration step may not be carried over to another planner group configuration step. At least one planner group should be defined for each valid plant. Unless used by another module, such as Production Planning, the SAP default planner groups (Planergruppe 1, for example) can be deleted.
Define Number Ranges for General Maintenance Task Lists
There is a separate number range for each of the task list types.This number range setting is to provide a range of numbers for general maintenance task lists. This number range is not shared with any other SAP module or any other task list type. See the section on number ranges for more information on configuring number ranges.
Define Number Ranges for Equipment Task Lists
This number range setting is to provide a number range for equipment task lists. This number range is not shared with anyother SAP module or any other task list type. See the section on number ranges for more information on configuring number ranges.
Define Number Ranges for Task Lists for Functional Locations
This number range setting is to provide a number range forfunctional location task lists. This number range is not shared with any other SAP module or any other task list type. See thesection on number ranges for more information on configuring number ranges.
Define Profiles with Default Values
At least two profiles should be configured for use with Plant Maintenance task lists. Two appropriate default profiles may beprovided with the system. One profile should be configured foruse with primarily internally (employee) processed work and theother profile should be configured for use with primarily external (contract, for example). The profiles provide default valuesfor the creation of task lists. If fields are not filled in a profile,some field values may need to be entered when creating a tasklist header or in each operation of the task list. Like wise, if a profile is not referenced when creating a task list, some field valuesmay not be defaulted.
Define Presetting for Free Assignment of Material
This setting is normally acceptable as defaulted. There should bea “4” in the configuration table. This allows the free assignment of materials to a BOM, etc.
Define Field Selection
This setting, not available in some version 4.6 releases and older, allows task list field attributes to be set. For example, specificfields can be set to be “display only, ” “required, ” “hidden, ” etc. There are numerous fields upon which the field attributes canbe influenced. For example, a specific field could be hidden based on the planning plant.
Maintain Control Keys
This is a similar setting to the maintain control keys setting in thework center section previously discussed. There are several settings in this configuration step that control whether tasks related to the control key are relevant for scheduling, costing, capacity requirements, printing, confirmation, and so on. Thereare several default control keys relevant to Plant Maintenance.
These begin with “PM” and in many cases may be adequate.Add others, if necessary, but take care not to alter or delete othercontrol keys that may already be in use, or may be used in the future, by other SAP modules. When the system is in use, thecontrol key in Plant Maintenance is assigned to each operation ofa work order or task list.
Changes made in this configuration step affect the same table inSAP as changes made in the define suitabilities section underwork centers. One or more qualifications may be defined here forlater use to determine whether a person is suitable or qualifiedto perform a task. This setting is specific to each plant.
Define User Fields
Additional fields that are not already defined by the system maybe added in order to record additional data in the operations of a work order. There are several different types of fields in orderto accommodate different types of data, such as character, numeric, date, etc.The fields are given labels in the configuration step and theactual values associated with each label are assigned in the workorder. The use of the user defined fields is not suitable for recording readings during completion confirmation.Maintenance of the field values is performed during the creationor changing of a work order.
The user field functionality is shared among modules, particularly the PP (Production Planning) and SD (Sales &Distribution) modules, so coordinate definition of user fieldsbetween the modules according to the field key.
Set List Editing for Task Lists
This configuration setting allows the setup of variants to search for task lists. Although the standard system settings allow for task list searching, it may be preferable to have several search parameters predefined in order to save time repeatedly entering the same selection criteria when searching for task lists.
Presetting for List Display of Multi-Level Task Lists
Within this heading, there are settings for each of the lists that may appear when searching for task lists under the multi-leveltask list search. As with the other multi-level searches, when using the system, a group of check boxes representing objectsthat may be associated with task lists appears. To view the associated date, the check box for each object must be checked. Therelated data is then displayed with the task lists to which it isassociated. These configuration settings define which fields aredisplayed in the list for each of the associated objects. The default settings are often a good starting point, but the default list displays may be expanded or restricted as necessary. If a fieldis not displayed by default, the system user can still display thefield by selecting it in the display screen.
Define PRT Authorization Group
Production Resources and Tools master records may be protected from changes by unauthorized users by using this setting.Standard SAP security does not provide security down to the level of individual objects unless authorization groups such asprovided in this setting are used. If protection at the object level is not required, changes are not required here. The creation and changing of PRT’s in general can still be protected with standard SAP security by restricting access to the transactions that allow the creation and changing of PRT master records.If security is required at the object level, determine whichvcgroups of PRT records will be restricted to which groups of users (roles), and then define the authorization groups in this setting. The authorization groups will then need to be assignedto the appropriate users/roles.
Define PRT Status
There are some default PRT statuses provided, which may be adequate. The PRT status controls whether a PRT can be usedat all, and whether it can be used for planning and/or production.Other statuses, if required, may be defined.
Define Task List Usage Keys
There are several default task list usage keys. Although only oneor two of the keys are normally useful in the Plant Maintenance module, the others are useful for other modules, particularly Production Planning. For this reason, it is recommended not to delete any of the default task list usage keys. Task list types are assigned to the task list usage keys as part of this configuration.
The only two keys that have the Plant Maintenance task list types assigned to them are 004 (Only maintenance task lists) and 009(All task list types). When creating a piece of equipment that is a PRT (Production Resources and Tools), using transaction IE25 instead of transactionIE01, an extra tab containing PRT-specific fields will appear. One of the fields is the task list usage field. If the equipment is to beused for Plant Maintenance purposes, the task list usage must be004 or 009, if the default task list usage keys are used.
Define PRT Group Keys
Production Resources and Tools (PRT’s) can be grouped according to the groups defined in this configuration step. There maybe some group keys already defined, which can be deleted if they are not useful. Note that PRT’s defined as equipment cannot make use of this grouping. Searching for equipment PRT’sbased on the PRT group key cannot normally be performed. PRT’s defined as materials, however, can use the grouping.
Define PRT Control Keys
This setting is used to control whether a PRT is included in the functions of a task list or an order to which it is assigned. An example of one of the functions is scheduling. A PRT may be excluded from such functions, if desired.
The two settings contained in the Formulas heading are SetFormula Parameters and Configure Formula Definition. The firststep is used to define formulas that are used or combined in thesecond step. The assignment of a PRT can be as exact and ascomplex as desired and with these settings, set up time, tear down time and numerous other factors affecting capacity planning and costs may be set. If such detailed tracking is not required, accept these settings as they are defaulted. Even if such formulae are required, examine the default formulas first. The formula required may already be defined.
Set List Editing for Service Contracts
This setting is usually only relevant for Customer Service functionality, but it controls the list editing displays for information related to service contracts. This configuration step is similar to the other configuration steps involving the definition of list editing.
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