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With the introduction of wireless field-side standards, such as WirelessHART and current efforts in SP100.11a standardization, gateway implementers are faced with making difficult tradeoffs between the robustness of any wireless solution being offered and the battery life of wirelessly-enabled sensors in the field. With more of the intelligence of the network being absorbed by the network manager/gateway function, gateway designers need reliable, proven solutions as building blocks for successful implementation.
Field programmable gate arrays (FPGAs) offer robust solutions addressing these needs. Vendors provide devices, embedded processors, intellectual property (IP), and complete protocol stacks for plant network protocols, enabling an end-to-end solution for companies wanting to implement various industrial applications.
FPGA benefits include:
Cost reduction - supports many product variants from one base hardware design;
Flexibility - FPGA can be quickly reprogramming for new features or increased performance; and
Protection from obsolescence - same hardware can be used for many customers.
System block diagram
A basic network manager/gateway system contains field-side radio modules for wireless communication, a core system processor, and a communication coprocessor implemented in a low-cost FPGA with an embedded processor. An FPGA offload the task of communication over the plant network, freeing the system processor to handle other core tasks such as managing the network. Implementing the protocol stack in an FPGA allows a single hardware design to support multiple plant protocols. This minimizes inventory costs, because users only have to stock a single gateway variant to support any plant connectivity required.
Engineering a solution to support multiple protocols is clearly possible by developing a series of plug-in boards, one for each protocol, but the number of standards and their constant evolution makes stocking such boards cost-prohibitive. Where standard Ethernet hardware...