Universal fieldbus interface reconfigures in software

Networks used for industrial communication have a variety of hardware for each. Minimizing communication hardware versions and reconfiguring only software for each network would lower costs.AG-E (Cincinnati, O.) has finished development of a single communication interface for major fieldbuses and Ethernet.

By Staff December 1, 2000

Networks used for industrial communication have a variety of hardware for each. Minimizing communication hardware versions and reconfiguring only software for each network would lower costs.

AG-E (Cincinnati, O.) has finished development of a single communication interface for major fieldbuses and Ethernet. AG-E says its V5 technology is an open, ready-to-use solution to integrate into PLCs, drives, motion controls, PC interface cards, fieldbus gateways, and other products.

By using the same host system hardware and software driver for all fieldbuses, AG-E expects lower costs related to design, inventory and production, and decrease time to market. In addition, several sources sell-off-the-shelf field-programmable gate arrays (FPGAs) eliminating single-source application-specific integrated circuit (ASICs). Re-configurable architecture and OEM tool kit eases future support for other fieldbuses or industrial communication networks. Examples include a new Ethernet protocol, such as EtherNet/IP or a specific manufacturer’s network.

The single hardware core reconfigures in software to support master and slave connections for DeviceNet, Profibus, CANopen, and AS-i bus. Only a change in the physical fieldbus connector is necessary, according to respective fieldbus mechanical specifications. A built-in TCP/IP stack allows support for Ethernet with various protocols. More fieldbuses and Ethernet protocols, including Modbus TCP, are expected soon. A fieldbus master configuration software program is available.

Architecture uses a FPGA

V5 hardware uses a FPGA to replace multiple, custom ASICs that normally provide the fieldbus Layer 2 stack. A library of FPGA software configuration sets is available for each supported fieldbus. The respective set is downloaded to the FPGA, which provides the layer 2 stack for the desired network.

The fieldbus application layer (Layer 7) uses a CPU, a multitasking real-time operating system (RTOS), and a deterministic task scheduler. A library of protocol drivers (corresponding with the layer 2 FPGA configurations set) supports each network protocol. Driver(s) are downloaded and executed under a hard real-time scheduling method that guarantees adequate performance for each driver task, AG-E says. The CPU handles the protocol and data exchange to the host system interface.

The Universal Bus Configurator (UBC) for the fieldbus masters—based on Microsoft Windows ActiveX components—can stand-alone or be integrated into another software product. UBC supports open interfaces for OEMs to add their configuration software for other networks.

Platform for tasks

V5 technology provides a platform for other automation tasks, including user written routines and off-the shelf programs. For example, the multi-tasking environment can execute a proprietary motion engine or a standard IEC PLC engine (available from multiple vendors, including AG-E’s sister company, KW Software, www.kw-soft wareusa.com , also in Cincinnati). OEMs can also add unique features or format fieldbus data for compatibility with their controller backplane.

An OEM Toolkit facilitates the user’s basic technology integration and helps in adding unique features. V5 FPGAs have three hardware integration options. (See online extra at www.controleng.com .)

For more info, visit www.controleng.com/freeinfo or www.kw-softwareusa.com/AG-E . See related product areas at www.controleng.com/buyersguide .