One important means of reaching the highest possible safety level in automation of life-critical respiratory support devices is redundant design: In this safety-critical application, two identical computer-on-modules based on the ESM™ standard are used to control several different types of ventilation devices. Those devices feature patient monitoring for invasive and non-invasive adult, pediatric and infant therapy in intensive care, post-anaesthesia care and in an emergency, e.g., through different methods of optimum respiration and precise diagnostics of the lung function.
The computing heart of each ventilation unit are two of the PowerPC® based ESM™ COMs EM1A. They are integrated in such a way that they monitor each other and they are tailored to meet medical requirements. Those include qualification according to IEC 68-2 for shock and vibration or MIL STD.810E for temperature and humidity, but also traceability during electronics production.
The application makes use of the internal interfaces of the MPC 5200B PowerPC® on the EM1A, including CAN bus, Ethernet, COM and USB, all routed to the ESM™ carrier board. The on-board FPGA is very complex and carries all application-specific functions. Depending on the version of the ventilator, up to 32 IP cores are loaded into it. Those include up to 8 UARTs for communication with the data logger, the microcontroller on the carrier or with different sensors for CO2 and oxygen measurements. They include up to 6 PWMs (puls width modulators) for valve control or for speed control of the ventilators. They include up to 60 GPIOs (General Purpose I/Os) and 2 SPI interfaces for time-synchronous polling of the analog digital converters.