An important aspect of PREVIEW is robust wireless communication. The wireless system is required to transmit sensor information from injection-moulding production cycles from Data Acquisition Systems to the Adaptive Processing Server in a timely manner. Besides other aspects, the quality of wireless connectivity depends on the environment in which wireless technology is deployed. The effects of obstruction for example, depend on the materials and geometry of obstructing and surrounding objects. Typically, metal is the prevalent material in factory environments which can induce less reliable multi-path signal propagation. Other challenges to reliability are interfering wireless technology and possible noise from machines using high-voltage power.
Whilst it is possible (and useful!) to describe the wireless channel by means of theoretical models, it is important to verify the model’s applicability by true life tests. Test results may also help to improve parameter selection in order to ensure that the models have a more realistic fit.
Humboldt-University ran a number of transmission tests with wireless hardware designated for the PREVIEW-prototype at Smithers Rapra; the same test was carried out at Promolding. Amongst the measured parameters were transmission delay, packet delivery ratio and receiver signal strength.
The results will enable a better understanding of the challenges of developing a robust wireless system. After all, reliability is essential for industrial applications.