Utilização do MES no desenvolvimento do SAP

sages were generated so as to avoid IT costs. Of course this meant that no improvement in the planning data could be expected, nor even realistic statistical cost accounting. For rigid production processes which have reached a steady state, a manufacturing company can under certain circumstances dispense with continuously updated status messages about the quality of the production process. In an age of increasing customer-driven flexibility this is no longer acceptable in a modem production line.

10.2.2 Requirements for an MES in the SAP system environment

The consequence of this was that subordinated systems had to be given a smarter design, in other words, brought closer to the process, with the aim of improving data quality by means of plausibility checks close to the process.

What close to the process means in this context is carrying out inspections reactively on the basis of the current production situation and the control inputs from ERP (target dates, target quantities, inspection and test plans) and reporting the results to ERP. These results trigger actions there or, by supplying the user with the corresponding information, put him in a position to be able to intervene in control.

The technical aim as regards IT is naturally to check the flood of data in the mySAP ERP system by preprocessing it and thereby reduce the IT costs for the SAP system. Examples of this include reporting milestones in materials management (MM) while transportation of material together with all material movements is secured in the MES, or accumulating quantities and times and time-ticket-related status messages in SAP PP.

At the same time it is important that mySAP ERP and the lower-level MES be adjusted to each other in such a way that no redundancy results. In other words, the systems must be so “meshable” with each other that for the user they represent a single across-the-board solution and the user, for example, only needs to carry out maintenance of master date in one system. The functions of the two systems should therefore supplement each other and under no circumstances overlap. This is the demand for a dedicated implementation in a manufacturing company.

A widely branched manufacturing company - in other words, a company which although it has a central IT department also has several production locations which come under different sectors of industry - will have another important requirement. The MES should be flexible enough to be configurable to the different production organizations but still ensure uniform integration with the central SAP system.

Depending on the production organization or sector of industry, one production location may need a shop-floor control function in the MES system while another location does not need this function or it is available in mySAP ERP.

10.2.3 Representation of levels in a manufacturing company

On the basis of this question, it is important first of all to structure the processes and system functions which are found in a manufacturing company and to ascertain the system (SAP or MES) to which they can or must be assigned.

In some very recent publications, SAP has defined the tasks and functions of a manufacturing company under the aspect of their assignment under the term MES. From these publications a levels concept can be derived which presents the processes and functions. These functions are grouped into levels.

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Fig. 10.1. Functional levels in a manufacturing company

Level 1a: Corporate planning

On the topmost level are found the classic ERP functions such as sales planning, capacity requirements planning, customer order management, sales, and shipping.

Level 1b: Planning and material planning for production

Level lb includes the functions for product planning, production flow planning and materials management. This also includes the supply chain management function which controls all logistical processing on corporate and subsidiary levels as well as logistics between customers and suppliers. This is to be distinguished from transportation management, or so-called intra-logistics (technical logistics), in other words, material control within the production department of the company, which is described below. On this level too we also find the SAP applications of APO. Here the time horizon for planning work is in all cases medium or long range.

Level 2: Production management

On Level 2 are found all of the processes which are largely used for implementation of the production plans produced on the level above. This is where flow of material and production itself are controlled.

On this level too are found functions and tasks such as reactive planning - in other words, production control itself, also referred to as shop floor control. The time horizon here is short range.

Level 3: Automation

Depending on the industry and/or production structure, this level includes functions which in the process industry/continuous production are largely handled by process control systems. In discrete manufacturing these functions for controlling the production process are for the most part mapped on the level of production control (shop floor control). On this level we also find not only all of the functions and processes in the manufacturing company which control the machines and installations but also those which are responsible for the exchange of information and control parameters to and from the machine or machine group.

10.2.4 Corporate processes in mySAP ERP and the MES system

In what follows, these functions and processes are assigned to the IT system mySAP ERP and to the MES system. For those levels situated “outside”, this assignment is conspicuous. The functions on Level 1 corporate planning are the classic disciplines of the ERP system and are covered by mySAP ERP. Even those functions for production planning and for the medium-range planning of materials and resources are for the most part implemented consistently in mySAP ERP.

The functions on Levels 4 and 5 are mostly to be assigned to the MES system or should at least be capable of integration into an MES.

Control of the production process is carried out in the MES system (process control function). This includes the classic data acquisition functions and naturally also the integration of the vital technologies for connecting machines, machine groups and process installations. The fundamental requirement is that all of the data are made available for the higher levels. This is the basis for ensuring the requirement for so-called vertical integration is satisfied.