Browse Publications Technical Papers 2005-01-1541

In Vehicle Communication With Solid Oxide Fuel Cell Using MODBUS Protocol 2005-01-1541

Integration of fuel cell Auxiliary Power Units (APUs) into vehicles requires that the vehicle Electronic Control Unit (ECU) communicate with the fuel cell controller using appropriate protocol. The common communication standard used in automotive systems is the CAN protocol. Some fuel cell controllers originate from stationary power scenarios and communicate using process industry communication protocols such as MODBUS. This paper reviews the MODBUS TCP protocol and CAN protocol. It then describes the MODBUS TCP software driver development for QNX Real Time Operating System (RTOS) used in the SwRI® Rapid Prototyping Electronic Control System (RPECS). The architecture of the communication system on the vehicle and details of RPECS needed to understand the MODBUS drivers are described. Tools such as RPECS™ and EtherPeek™ (TCP/IP packet sniffing software) used during debugging are also briefly described. A new mapping method for conversion between MODBUS and CAN protocols is proposed.
This work has been developed at Southwest Research Institute on the SunLine Project, funded by US Army National Automotive Center.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 40% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.