Three channel temperature sensing node for sensor on bus approach

This article describes the design and evolution of multiple temperature sensors at a single node with inbuilt fault detection mechanism. The sensor node consists of three thermocouples interfaced with MAX31855 and a microprocessor. The actual temperature is obtained by MAX 31855 and the digitized output for all sensors is transferred to micro processor on SPI along with their health status. This sensing node is an active module on a CAN bus which delivers sensors data to master on reception of a remote frame. Upon reception of request, all the sensor data is offered to this bus at one mega hertz in a single data frame. The measurement result is send to PC serially via USB Bridge. The sensing node designed operates on single low power supply. The complete chain of data communication is tested to get ten samples per second suited for all thermocouple applications.