SelectTrust®

SelectTrust is the first technology worldwide to be able to guarantee a verifiably correct manual data entry using a touch screen. To do this, SelectTrust generates a second reference information from the displayed image data stream and the touch information – independently of the information path of the ‘classical’ touch event. The safe computer checks the classical operator information for correctness by means of the reference information.

Along with IconTrust® , SelectTrust provides a cost-effective solution for safety considerations and proof of compliance with current safety requirements. Both monitoring systems work fully decoupled from the display function and operating function making them unique in their mode of operation.

SelectTrust ensures correctness of operator input on a HMI equipped with a touch panel by selecting the depressed control element via IconTrust®, allocates it a signature and transmits the corresponding proof total to the safe computer. The information from the ’classical’ Touch Event is compared with the SelectTrust signatures using previously determined reference charts. Reliability of the information is ensured.

With SelectTrust both safety relevant and non-safety relevant information can be realised within one HMI unit. In this way, SelectTrust enables use of more powerful standard PC technology and its associated advantages such as cost efficiency, ergonomics, flexibility and variability for the safety critical area.

For the user the technology is invisible. On the TFT he chooses a displayed graphical control element and touches it. The coordinates of the touch point are transmitted and the touch event is activated via drivers, operating systems and application software. Using the coordinates, the information contents are now allocated and transmitted to the addressee. SelctTrust and IconTrust® monitor only safety relevant areas.

Multi-function terminals must be retrofitted with appropriate mechanisms for revealing errors, if they were realised using modern computer science and are used for the inputting and outputting of safety relevant data.

Considerable cost savings can be made throughout the life cycle of these IconTrust® Multi-function terminals, since verification management is limited to complying with the conditions of use. Updated verification is required for project and product adaptations only when safety relevant areas are affected. Changes in display contents with no safety relevance have no effect.