Plant asset management - Products for intelligent maintenance

2 Introduction How can the productivity of a plant with a high level of automation be increased even further? Surveys have indicated that plant operators in all sectors consider increased availability and shorter downtimes to be the most effective lever toward increasing productivity. Investigations have shown that downtimes are frequently the result of insufficient maintenance – despite the fact that maintenance is already a significant portion of the lifecycle costs. Intelligent maintenance strategies can make a significant contribution toward increasing productivity: ■ Failures can be prevented by monitoring the current plant condition. ■ Maintenance can then be planned. maintenance is not left until a fault has occurred, but already provides appropriate measures in advance for avoiding faults. The timing of maintenance can be planned such that the existing resources can be used optimally. ■ Innovative maintenance strategies pay for themselves twice: planning security and the specific application of methods reduces the direct maintenance costs. ■ Plant availability is increased at the same time. This means that consequential costs resulting from failures, such as quality deficiencies or loss of image, are reduced. Totally Integrated Automation supports intelligent maintenance strategies. The SIMATIC Maintenance Station is of significant importance, and presents the information relevant to maintenance from all automation components in a uniform and clear manner, thus providing the maintenance engineer with valuable support for making decisions. Maintenance strategies There are two maintenance strategies: response to failures or taking preventive measures. In the case of failure-oriented cor-rective maintenance, measures are only initiated when a fault has occurred, i.e. failures are acceptable in this case and may be minimized by a redundant plant design. The objective of preventive strategies is to already carry out maintenance measures before faults occur in order to prevent downtimes which may possibly result. This strategy can be satisfied using time-dependent and load-dependent measures. Regular maintenance work is an example of time-dependent measures. The load state is determined from the number of switching operations, operating hours or load peaks. Condition Monitoring, that is to say status monitoring, aims to detect imminent errors at an early state. provides information on the remaining duration of use. In the case of condition-based maintenance, the maintenance measures are only initiated when the period of use has expired. It has been shown in practice that optimum results can be achieved through intelligent combination of the different strategies. Higher operating expenses for condition-based maintenance will be …