Vote for this product, until August 23rd, 2019 (see category A, company K.A. Schmersal)
The SLC440/COM with Bluetooth BLE is an Active Optoelectronic Protective Device(AOPD) that makes all status and diagnostic data on the operating status available on smartphones or tablets via a Bluetooth interface. Bluetooth Low Energy (BLE) is a radio system for near-field data transmission with secure transmission technology. This status information and diagnostic data enables processes to be reactivated more quickly, particularly in the event of a system shutdown. All operating data can be stored and is available for further processing. The Bluetooth interface also supports easy start-up using.