Assessing accuracy of machine CAN bus data using SAE J1939 and Nebraska tractor test laboratory data

There has been a growing trend in public and private groups focusing on data utilization in agricultural settings in the U.S. over the past five years. This information, typically referred to as Precision Agriculture (PA) data, has advanced from field collected data (e.g., yield and soil samples) to data that many producers may never see. Controller Area Network (CAN) Bus is one example of data rarely perceived by those operating field machinery; however it is crucial to the machine functionality. This information is becoming more widely used by groups (manufacturers, dealerships, and data management companies) seeking to utilize these data for realtime applications including machine diagnostics, machine health monitoring, and field efficiency estimations. The Society of Automotive Engineers (SAE) J1939 standard messages utilized by the machine CAN Bus have theoretical values, however little work has been done to verify these values. For example, fuel flow rate values reported are rarely measured directly on field equipment using a flow meter, and must be therefore estimated based on other operating parameters. The goal of this study was to compare data collected from the CAN Bus to measured values from tests conducted at the Nebraska Tractor Test Laboratory (NTTL), an approved OECD Test Station to provide an indication of accuracy among the measured values. A National Instruments LabView program was written to simultaneously log CAN Bus messages along with the NTTL test data. Selected parameters from the SAE J1939 message data base were then compared with actual steady-state values measured during testing. Results from this study will provided needed information regarding the accuracy of certain messages being passed on the CAN Bus. This will give end users the ability to assess potential errors that may exist when the CAN Bus is utilized as a data source for further analysis during real-life scenarios of machine utilization. As initial results indicate, the CAN based fuel rate is measured higher than actual fuel rate, so more data collection will be required to find the correlation to aid in a more accurate assessment of in field efficiency measured via CAN bus.