M.J.M. van der Horst
Architectures of ERP systems.
Literature survey,
Report 2003.TL.6755, Transport Technology, Logistic Engineering.
Enterprise Resource Planning systems can be divided into three main areas
of industry. The MRP II based ERP is mainly found in the more complex,
batch oriented industry, for instance in bicycle factories. Process
manufacturing ERP appears mostly in the process areas, such as chemical or
food industries. Project planning is used in single projects, like
building a factory.
MRP II based ERP is a business oriented closed loop integrated planning
system, consisting of several modules. The core manufacturing component is
MRP II, of which MRP is a subcomponent. MRP is a linear planning system,
it is built around the Bill of Materials (BOM) with the three main
functions, netting, batching and time phasing. MRP evolved into MRP II, a
closed loop planning system that has scheduling and planning components
and that takes into account the Company's master plan. MRP II creates a
routing. This routing specifies the sequence of operations, the machine or
work center, the tools or fixtures needed, process instructions, and the
setup and run hours for each operation. The routing, the BOM and
information from the work centers schedule the orders.
Baan and SAP are two MRP II based ERP manufacturers. Their respective
systems, BaanERP and SAP R/3, are discussed in paragraph 2.4.
BOMs appear in four different forms, linear, converging , diverging and
general. These BOMs have to be put into a matrix form for them to be
processed by software systems. The first step is make a gozintolist, from
there chapter 3 shows how to create the matrix form of a BOM. With this
matrix form total demands for ingredients and parts can be calculated and
a production planning can be created.
Process manufacturing ERP is used in the process and the semi-process
production environments. Process manufacturing ERP combines the BOM and
routing into one structure. The main focus is on activities with their
attributes, such as capacity and materials needed. In paragraph 4.2 two
manufacturers of process manufacturing ERP are looked at, Protean from
Invensys and iRenaissance from Ross.
Project planning systems provide systematic procedures for planning,
scheduling and controlling projects. The two main scheduling techniques
are the critical path method (CPM) and the program evaluation and review
technique (PERT). Both techniques are almost similar and the biggest
difference is that PERT is able to deal with uncertainty in activity
completion times. For this PERT uses a three-estimate approach with a beta
probability distribution.
The basis background of the ERP systems is known, but the implementation
used by the manufacturers is mostly a secret. To really find out how one
system works, help is needed from that particular manufacturer
Reports on Logistic Engineering (in Dutch)
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