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PCI EXPRESS Figure Fig ig igu gure 4. 4 This Th T is ATX TX T form fo f rm factor fa f cto to t r expansion ex exp xpansion back-backplane contains direct PCIe cable connections. the PCIe cable is equal to the PCIe backplane rate, the performance of this repartitioned system is equal to the architecture where the CPU board is in the native form factor of the industrial bus. PCIe can also be used for direct communications between PCs. In this model, PCIe over cable can be used for high-speed memory-tomemory transfers and/or used as a very fast TCP/IP connection, with application compatibility to standard Ethernet. Direct data transfers are used in designs that send data from one PC memory into a memory of another PC as rapidly as possible. This is particularly useful for multi-computing applications where one PC inputs data and then passes it to a second PC for data manipulation. This PC then passes the data to another PC for graphical display, and another PC for storage. In this example, the PCs could be physically separate communicating with PCIe over cable. The TCP/IP mode allows users to utilize TCP/IP applications to conveniently communicate between PCs, map and share disk drives, printers, etc. Applications that are adopting PCIe over cable for local networking include medical imaging, document center internal data transfer, instrumentation data sharing and high-performance computing inter-networking. Whether used for high speed I/O, bus expansion or as a high-speed network, there are several advantages associated with PCIe over cable – low cost, low power, high bandwidth and software transparency. These advantages derive from the fact that CPU components and chip sets nowadays directly drive PCIe as their expansion bus. Thus, the PCIe cable adapter cards are quite simple. The adapters simply route the signals from the motherboard out to the PCIe cable connector, and provide some signal conditioning to guarantee the signal integrity is met at the other end of the cable. Because these adapters are simple, they are inexpensive. Because they do not convert the PCIe protocol into anything else, they are the high performance and do not require any software drivers (for the I/O expansion models). As an I/O expansion protocol, PCIe can be used in place of other protocols including: Starfabric, external SAS, Fiberchannel and USB. Compared to each of these, PCIe is the highest performance since there are no protocol conversions or timing delays. No cable connection can transfer data faster than the PCIe slot is capable of, and PCIe over cable is by definition at 100% performance. Any adapter that has to convert PCIe into a different protocol, send the data over the cable, and then convert it back to PCIe at the other end of the cable so that it can communicate with I/O devices, will necessarily be slower – both in throughput and latency – than a pure PCIe over cable solution. For networking, the comparison is PCIe versus 1Gb and 10Gb Ethernet. 1Gbit Ethernet is clearly the most well accepted and lowest-cost solution. 10Gbit Ethernet continues to demand high prices, particularly for switches, and is used sparingly. PCIe over cable is much higher performance, but also more expensive than 1Gbit Ethernet. PCIe over cable compares favorably, however, to 10Gbit Ethernet. In this comparison, PCIe spans a much broader performance range – 2.5Gb/s for a x1 Gen 1 up to 128Gb/s for a x16 Gen 3 – than 10Gbit Ethernet. June 2011 22 In general, a PCIe network will perform 2 to 4 times as fast as 10Gbit Ethernet, while requiring half the power and costing half as much. The PCI-SIG cable specification does not specify fiber optic solutions for PCIe. Several vendors have however introduced active fiber optic cable products for PCIe. These cables plug into the standard PCIe over cable connector and then convert the signals into optical signals and send them over fiber optic cables. The primary advantages of these products is that the fiber cable can span considerably longer distances – typically up to 500 meters, and that the optical signals are completely immune to EMI interference. Two types of applications are utilizing PCIe over cable with active fiber optic cables. First are outdoor data acquisition and security systems where the distance feature is key. The second is within heavy industry factory floor applications where the fiber optic natural immunity to EMI (from welding and other machines) is key. PCIe was originally defined to support CPUto-I/O communications, with a single PC serving as the bus interface host. Multi-computing can be accomplished using PCIe through a combination of non-transparent bridging and CPU-to-CPU communications software. This technology expands the applicability of PCIe to a wide variety of high-end applications, including radar and sonar analysis, medical imaging, test and measurement and high-performance computing (HPC) inter-communications (figure 4). The use of PCIe as a networking architecture is beginning to gain significant traction. This applies both to inter-blade communications (within a blade server) as well as external PCIe over cable connections between servers. Large HPC clusters with hundreds of interconnected nodes are currently being designed based on PCIe networking. The ability to run PCIe over cable at full performance with software transparency opens up a range of new application possibilities for CPU-to-I/O system re-partitioning. Low-cost host bus adapters extend the PCIe bus structure to expansion chassis or dedicated PCIe I/O hardware. PCIe over cable provides a simple and low-cost method for extending applications that need more I/O boards than will fit in a single chassis to a multi-chassis solution. PCIe over cable can also be used as a high performance peripheral connection – a super-fast USB of sorts. Designing compatible end-points is straightforward because the PCIe interface is available as a gate array library. When CPUto-CPU communications are added to PCIe, the cable interface can be used as a high performance cabled network. A x8 cabled network with Gen 2 timing will transfer data at 40Gb/s – or 40 times faster than 1Gb/s Ethernet interfaces today. n
Case study: automated control of a CNG filling station Alexey Ryabinin and Dmitry Lopatin, Fastwel The article describes the automated control system for an automobile CNG filling station (ACNGFS) developed by JSC Krona. The system features high-performance and highly reliable MicroPC controllers from Fastwel (OC Linux 2.6) and IEC 61131 3 compatible software ISaGRAF 5. n An automobile CNG filling station (AC- NGFS) serves the purpose of refuelling cars or other vehicles that use compressed natural gas. The gas reaches the ACNGFS through the regional gas pipeline system. At the station it is pressurized to a certain level in readiness for pumping into the fuel tanks of vehicles. Structurally the ACNGFS in Tosno, near St Petersburg, figure 1, consists of three independent compressor units (CU No. 1, 2, 3) and general equipment including four gas station dispensers and a gas tank, or accumulator. The gas is compressed and pumped into the accumulator at up to 235 atmospheres. Refuelling is performed from the gas accumulator. An ACNGFS flowchart is illustrated in figure 2. The customer requested JSC Krona to replace the outdated control system of the ACNGFS with a modern one, putting particular emphasis was on the need for reliability, usability and easy maintenance. It was specifically required that the operator’s control panel software should be of high quality, confirmed by the ISO 9001:2000 quality standard certificate. The structure flowchart, figure 3, shows that the automated control system (ACS) which was developed consists of two main parts, the control cabinet and the operator’s control panel. The control cabinet is fitted with a Fastwel CPC108 controller running Linux 2.6 with Target ISaGRAF 5. Analog signals are trans- mitted from data sensors to intrinsic safety barriers in the control cabinet and then to Analog Devices 7B signal conditioners with galvanic separation. Then they are sent through the analog signals multiplexer (not shown in figure 3) to Octagon Systems 5710 analog input/output card. Input and output discrete signals from the pressure indicators and actuators are sent, in one or the other direction, through intrinsic safety barriers, signal conditioners with galvanic separation and Octagon Systems 5600 discrete input/output card. The operator control panel consists of two computers with the Winlog SCADA system and a back-up control panel. Computers are connected to CPC108 by means of Ethernet TCP/IP through an Advantech EKI 2528 AE 8port uncontrolled switch. On the back-up control panel there are IEE indicators connected to the CPC108 through RS 485, and control keys connected to the 5600-cards through KP10 conditioners. Hardware from Fastwel and Octagon Systems (figure 4) was chosen as the platform for the new control system. The choice was conditioned by several factors: high quality; optimal price/performance ratio; many years of positive first-hand experience of using this hardware for control systems development. Thus, the ACS was basically designed using the following hardware. Master device (MD): Fastwel EMBEDDED COMPUTING Figure 1. Automobile CNG filling station in Tosno (near St Petersburg) CPC108 03 processor module with ISaGRAF 5 target system running Linux 2.6; Octagon Systems 5710 analog input/output module; Octagon Systems 5600 and Fastwel UNIO96 1 discrete input/output modules. Process interface devices: Analog Devices series 7B analog signal conditioning modules; discrete input (KP10 series) and output (KP20 series relay modules); signal conditioning modules (JSC Krona); Iskra intrinsic safety barriers; KP10A analog signal multiplexer. All MD modules are in MicroPC format. The processor module actually serves as a controller. Module 5710 works as an analog-to-digital converter. The universal 96-channel input/output module UNIO96 1 is programmed to perform discrete input/output for the required purposes. Programming was based on the ISaGRAF 5 system which complied with all technical specifications and met the management demand to switch to standardized software. Before 2008 hardware programming was based on the software developed by the company itself. The MicroPC-ISaGRAF 5 tandem was selected as the basis for the hardware/software complex, having the following advantages. MicroPC devices have high performance and are able to operate a significant number of input/output points with heavy computation loads. Standardized programming languages and convenient development and adjustment environment sig- 23 June 2011
Page 1: COVER STORY Multi-core processors a
Page 4: CONTENTS Viewpoint 3 ATCA, MTCA & A
Page 7 and 8: Fi Figure 11: Si Simplified plif if
Page 9 and 10: n ELMA: 12-slot xTCA system with re
Page 11 and 12: Figure 1. CPU-to-CPU connectivity u
Page 13 and 14: terconnected via a high-performance
Page 15 and 16: an integrated 1U fan drawer. Fitted
Page 18 and 19: COMPACTPCI A straightforward x86 em
Page 20 and 21: PCI EXPRESS Using PCI Express as hi
Page 24 and 25: EMBEDDED COMPUTING Figure Fig ig ig
Page 26 and 27: EMBEDDED COMPUTING A new processor
Page 28 and 29: EMBEDDED COMPUTING hundreds of othe
Page 30 and 31: PRODUCT NEWS n VIA: Mini-ITX board
Page 32 and 33: PRODUCT NEWS n NEXCOM: rugged trans
Page 34: PRODUCT NEWS n DDC: avionics 1553/4

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