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EETE JUN 2015

- CAN bus communication for data security and transmission speed - EMC compliance for industrial applications (NF-EN55022 and/ or NF-EN61000-4-3) - Multilingual management to use the charging station everywhere in the EU - Half-finalized product delivery, ready to be integrated into its final application The business application already existed, therefore the new touch HMI had to be developed from this existing application. On its other charging station models, the manufacturer had previously chosen an embedded Linux solution, therefore encountering some development time constraints. Unable to develop a new graphic HMI that could communicate with its business application through CAN bus, the manufacturer had been looking for a backup solution that would guarantee a reduced development time (less than 4 weeks), a complete offer (hardware, software and graphic design) with a proprietary OS and a complete customization of its screens. By choosing Clairitec’s HMI solution, the manufacturer has been able to develop its HMI directly from its existing business application through CAN bus and with a simple set of commands (maximum 20-25 commands). The HMI products by Clairitec are compatible with every display on the market, hence the choice has been focused on a 7” WVGA reference display with 1000cd/m² of brightness and a wide viewing angle (90°) in order to guarantee optimal reading no matter the position of the user in front of the station. In parallel, we have chosen a projected capacitive touch panel (P/CAP) directly integrated on a 6mm thick cover glass in order to guarantee the IK10 compliance (resistance to a 5kg mass falling from a 40cm height). This touch panel is also waterproof which is very important for an outdoor application. The main problem in very bright environments is not the brightness but the contrast. The contrast is the ratio between the levels of black and white; in other words this ratio defines the brightness difference between the brightest white pixels and the darkest black pixel. We have therefore done an optical bonding between the display and the strengthened cover glass. This method allows to increase the contrast of the display by reducing the amount of light reflected. An adhesive film with special optical properties was used to remove the air layer between the cover glass and the display but also to prevent the presence of particles and foreign fluids within the interstices and to prevent condensation. Using optical bonding along with an anti-reflective film surface treatment significantly increased the optical performances of the display. The SpiderGraph HMI board was recommended since it is equipped with an integrated graphic engine, has a 32 Mo memory capacity, is able to display up to 65535 colours through a 16-bits LCD TTL output, directly manage the touchscreen and communicate through a RS232 or CAN serial connection. www.electronics-eetimes.com Electronic Engineering Times Europe June 2015 33


EETE JUN 2015
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