Scheduling of Production Resources/Tools
In the SAP system you can schedule production orders that use production resources/tools (PRTs) based on the availability of the latter. Maintainable PRTs of the Equipment category are used.
You can only use this function for production orders. It is not available for process orders.
You can schedule production orders using a SAP-APO system.
Checking the Available Capacity of PRTs
To check the available capacity of a PRT, you have to create capacity master data describing the available capacity of each PRT:
· availability on a particular date
· number of available PRTs
· usage costs
Master data of this kind is present in SAP R/3 in the form of work center master data.
If you wish to use the SAP APO system for planning, the master data is available there for each resource once it has been transferred to the APO system.
To create available capacity for a PRT, you must first create a “virtual” work center with work center category PRT. In the capacity header of this work center enter the dates when the PRT will be available (operating time from/to, factory timetable, shifts, etc.) In the case of PRT pools enter the number of interchangeable members in the pool. On the Costing tab page also enter the costs to be debited to the production order when the PRT is used.
Then enter this “virtual” work center on the PRT tab page in the master data of the PRT (in this case, Equipment). If you are using a PRT pool, you must also assign the virtual equipment that represents the PRT pool to this virtual work center.
You can link a PRT to an operation either as a single, physical PRT or as a pool PRT. A pool PRT is equipment that contains a single-level structure of subequipments.
The pool PRT is not physically available but it represents the total number of physically available PRTs.
These subequipments are physical PRTs that all have identical characteristics and can be used interchangeably at a work center. Consequently, it does not matter which equipment in the PRT pool is used as the PRT. However, a PRT’s item number in the structure determines the frequency with which it is used when the pool is automatically replaced with the physical PRT: PRTs with lower item numbers are given preference if they are available on the given date.
Assign the required PRTs to the operations in the routing. Then, in the routing of each operation that uses the PRT, you must create – for each PRT – a suboperation that uses the virtual work center of the PRT. Because the operation times of the PRT suboperations correspond to those of the higher-level operation (for grouping category 0), scheduling of the PRT is linked with the scheduling of the higher-level operation.
If you use the SAP APO system, the PRT suboperations appear in the PPM as a separate operation with an activity performed using the resource that is linked to the PRT as a (virtual) work center. This separate operation is performed in parallel to the operation that uses the PRT.
Ensure that no operation or suboperation number occurs more than once in the routing – not even across operations. The combination Operation 10 – Suboperation 10 leads to errors, as the SAP APO system uses both numbers to create the two APO operations.
Ensure that the same work center is entered in the routing and in the equipment master data. The system does not automatically compare the work center and equipment data. Errors may occur in planning if the work centers differ.
When you create a production order, the system checks if the PRT (or any other PRT in the pool) has capacity available at the specified time.
If a PRT is available, the desired date is confirmed.
If no PRT is currently available, the system displays the capacity utilization of the PRTs. You can then manually schedule the production order or have the system propose the next date the PRT is available based on a user-defined strategy in capacity planning.
If you use the SAP APO system and alternative resources are available in the PPM (see below), you can schedule these alternative resources for the operations in the detailed planning tool or cause them to be scheduled by means of a heuristic.
Replacing a Pool PRT with a Physical PRT
If capacity planning for the PRT is carried out using a PRT pool, you must automatically or manually replace the pool PRT with a physical PRT in the PRT pool before releasing the production order in SAP R/3 (or more accurately, when you print the shop floor papers). The transaction Replace PRT in Order is available for this purpose.
Failure of a PRT
If a PRT breaks down during production, it can be replaced with another PRT. Again, you can use the transaction Replace PRT in Order to do this. The new PRT should be used prior to the next completion confirmation in the production order operation so that the correct PRT is debited, in terms of capacity and costs, when confirmation is made.
Alternative Modes in PPM
You can use the SAP APO system to schedule PRT capacities. When a routing is transferred from the SAP R/3 system to the SAP APO system, its suboperations are mapped in the PPM as separate operations with an activity performed using the resource that corresponds to the work center of the suboperation. The suboperation resource corresponds to the capacity of the PRT. When you create an order in the SAP APO system, the system checks, in the course of scheduling, whether all required resources are available. The order is then either scheduled on the desired date or reschedule for a different date, depending on when the resource is available.
In the SAP R/3 system you can create alternative routing sequences to the standard sequence. The operations/suboperations in the alternative sequences can occupy other work centers and other PRTs.
When data is transferred from the SAP R/3 system via the Core Interface (CIF) to the SAP APO- system, the alternative sequences become alternative modes. As a result, other resources can likewise be occupied by the operations.
The operations in the alternative sequences and the operations in the standard sequence must be identical between the branch operation and the return operation. In other words, the alternative sequence must not contain any additional operations nor may it contain fewer operations. Only the work centers used and their operating times may vary. If you want to use alternative sequences with different operations when manufacturing a product, you must create two production versions; this leads to two different PPMs in the SAP APO system.
Logically related machine and PRT groups are created as a result of mode linkage in the SAP APO system. These groups remain intact even if an operation is moved from one resource to another.
Note 576492 must be installed in the system if you want to be able to transfer alternative sequences to the SAP APO system.