Elf2-Based Small, Smart Networkable Appliance
Overview: RLW’s S2NAP is the first in a family of devices intended to support distributed monitoring and control applications in a truly open networked environment. The S2NAP provides data acquisition for up to nine channels, output on up to three, signal processing for advanced machinery monitoring and control applications, and XML-based communications over any network.
Goal: To have a low-cost device that can be easily integrated with machinery and IT systems to provide near–real-time health assessment of machinery, using any analysis algorithm with any combination of sensor inputs and report results over any type of network.
Challenge: Flexibility! The S2NAP needs to be able to operate in a variety of network environments, ranging from serial buses to wired Ethernet to wireless LANs of all types. RLW decided on a flexible solution based on using PC-Card format Network Interface Cards (NIC) as appropriate to the application. From a software standpoint, using open-source Linux on the S2NAP provided adaptability.
Solution: SECO USA’ Elf2 platform met RLW’s requirements. Elf2 provides a low-power, high-performance StrongARM microprocessor running Linux and two PC-Card slots. While realizing the raw signal processing horsepower that control and sensing applications demand on a separate SHARC DSP board. Integration between the SHARC-based core processor and the Elf2 is straightforward via a serial connection. The S2NAP consists of three boards: the Elf2, a DSP coprocessor and an I/O module. The I/O Module implements analog input for eight sensor channels, one tachometer input, two analog outputs, and one relay output. Two 16-bit, 60kHz A/D banks allow simultaneous sampling and digitization of two channels. The I/O Module interfaces digitally to the Analog Devices SHARC DSP based Core Processor (CP) for sensor signal processing and control. The CP produces XML-formatted output, which goes to the Elf2-based Network Processor (NP), via a serial connection. The Linux based Elf2 manages all network traffic for the S2NAP and hosts the appropriate PC-Card based NIC for the application. The three boards are matched to the Elf2 form factor and are arranged as a stack in an industrial enclosure.
Benefits: “The development of the S2NAP software on the Elf2 was greatly facilitated by SECO USA’s Linux board support package and outstanding tech support” said Bill Nickerson, Vice President of RLW, Inc. “The Elf2 provided the small size, low power, peripheral rich platform we required for our application.”