Operating resources: machine or installation section

machine, the machine group or the plant section. Defining the individual work centers is process-dependent in the MES system and will therefore only be oriented to a limited extent by the requirements of the ERP system.

With the MES system being based on a more finely implemented machine Fig. 6.2. Selection of data entry objects

6.4 Operating resources: machine or installation section 123 definition, a production line in MES will therefore in most cases be broken down into individual machine groups since the process steps active there form the basis for data acquisition.

The production speed, the quantities produced of good or poor quality, and also the reasons for and durations of idle times are the main data which are acquired at the machine.

6.4.1 Order/operation

An order originates in the ERP world and with its plan requirements de-termines the targets for the production process. At the same time it serves as a cost collector for recording services performed (times) and quantities produced. For this reason the order represents the backbone of data acqui-sition and is thus the classic data entry object.

Anyone in the field of data acquisition talking about the order in most cases means the operation, the operating sequence or the activity. The op-eration includes all information which according to the work plan relates to the corresponding work center and to the process step within the order.

The work operation transports production information to the data acqui-sition station. This data includes master data from the work plan (standard speed, planned work center, planned set-up time, planned running time, work instructions) and from the material master (bill of materials informa-tion, required quantities, drawings) as well as the descriptive data for the order (such as target date and target quantity, and possibly customer in-formation, printed text for labels, and so on). The work operation also de-termines resource requirements, which in production are assigned and plausibility checked either implicitly or by manual inputs as an MES sig-naling object.

At the same time the work operation receives information from the pro-duction process about the progress of propro-duction and displays this at the data acquisition station, transfers information into the MES database and collects feedback data for the ERP system.

In addition to pure production orders, an MES also processes reworking orders, project orders, overhead cost orders and inspection orders, which may very well be handled differently within the data acquisition process.

6.4.2 Material

Data acquisition may relate not only to those materials which flow into the production process but also to the material produced. In the case of incoming materials, in most cases plausibility checks are carried out against the bill of

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material. If a manufacturer is required to register and track on a batch basis, he will need to identify the material batches in the production process at the data acquisition client. Discrete quantitative consumption which is measured at the work center also represents a material-related report which can be passed on to materials management.

Manufactured materials are logged as yield, scrap and reworking quanti-ties. For concatenated processes with charge-based data acquisition the MES system generates unique batch or lot numbers for further tracking purposes. Materials can be barred directly in production and in this case cannot be used further until a decision is made about their future.

6.4.3 Resources and production tools

Resources which are required for carrying out the production process and which are simultaneously only available in limited capacities are included in the planning, are assigned and then taken up by the production process.

This includes the tool, specially trained personnel, such as the line engi-neer or the quality representative, as also special handling devices or re-quired items of equipment.

In many production environments the tool as a resource is even more important than the machine. Tool-related maintenance is based on regis-tering service times and quantities (work cycles). Recording the tool num-ber will be an unavoidable requirement when several tools of the same tool type are being used, such as is normal in large quantity production, for example. On the other hand it will not be necessary if only the planned tool is used.

Active resources are barred with respect to parallel scheduling and use in other machines.

Machine programs or machine settings records are special resources which the terminal transfers into the machine controller during the set-up procedure. Monitoring release criteria and versions management are also tasks the MES system must perform for these resources.

6.4.4 Process values

In the case of highly automated processes and in production environments in which product quality is markedly dependent on individual process val-ues, a central role is played by the recording and the permanent monitoring of characteristic process values. Here MES data acquisition records the relevant signals direct from the process (analog or digital), displays them and saves them in the database, either on the basis of specified random

6.4 Operating resources: machine or installation section 125 sampling patterns or at defined intervals. In the case of batch-based pro-duction there is frequently a need to save recorded process values in rela-tion to the batches of material produced.

6.4.5 Personnel

The aim of data acquisition relating to operating personnel is to be able to assign the work done to a cost unit such as, for example, the production order, the maintenance or overhead costs order. Personnel-related mes-sages in production are registered in an integrated MES system combined with clocking-in and clocking-out data. This means that attendance times can be compared with productive working times at the workplace. If per-sonnel are working on the basis of performance-related remuneration mod-els, the worker’s cost-center–related or order-related messages will form the basis for calculating the corresponding time balances for the incentive payment or piecework models held in the system.

Target/actual comparisons, such as current personnel overviews, for ex-ample, are based on the personnel messages of the workers.

Identification of the individual plays a central role in the implementa-tion of access control requirements. In this regard the MES system sup-ports not only conventional card readers but also special data acquisition techniques for checking biometric data, such as fingerprint readers or even retina scanners. The job of the MES system is to manage the reference bit pattern for each person for comparison purposes during the identification process.

6.4.6 Inspection and testing characteristic

The inspection order tells a production process at what time or quantity-related intervals individual characteristics of the material being used or manufactured are to be subjected to inspection. The job of MES data ac-quisition is to record the inspection results, to compare target values and tolerances, and also to display characteristic curves, for example, in the form of control charts, Pareto analyses or analyses from statistical process control. What is particularly important here is one particular function of some MES systems whereby irregularities or deviations from target re-quirements are immediately displayed upon data input or measurement.

126 6 Integrated production management with MES