When accounting for the unreliability of the voting circuits, we see that the voting circuits themselves are redundant in the tmr configuration. Figure 1 shows, in simplified terms, the basic structure of the trusted tmr processor module. Pdf on jan 1, 2017, mohammed hadifur rahman and others published a fault tolerant voter circuit for triple modular redundant system find, read and. Triple modular redundancy continuous time markov chains. Triple modular redundancy tmr is a suitable fault tolerant technique for sram based fpga. Each obc has different priorities in transmitting and receiving data, while. Triple modular redundancy, a proper noun, is a based on proven statistics and stringent mathematics. Triple modular redundancy triple modular redundancy tmr uses three functionally equivalent units to provide redundant backup. Revisions to conventional clock domain crossing methodologies. Download the technical manual for wiring and installation instructions. Parallel processing along with triple modular redundancy tmr has been used to increase the operating speed of the system and also to make the system fault. In this article we will go over the most usual options to configure a redundant architecture. Requires identical system inputs voted before agreeing on the one input set that will be. Redundant logic tr0 redundant logic tr1 redundant logic tr2 output package pin tmr register with vot e rs and r e f r es h tr0 tr1 tr2 tmr o u tput ma jo ri ty v o te r size fpga a b figure 1.
Revisions to conventional clock domain crossing methodologies in triple modular redundant circuits author. The method has a circuitry overhead which is comparable to that of the triple modular redundancy tmr scheme, although it is shown to have a reliability, and more importantly a mean time to failure, improvement well beyond that expected from the standard tmr systems. If any one of the three system fails, the other two systems can correct. Tmr is more reliable than dmr due to two main aspects. A vhdl approach has been developed for automatic tmr insertion and a demonstration design has been developed. Comparative redundancy, an alternative to triple modular. Basic concepts of redundant architecture of plc plcdesign.
The effects of race conditions when implementing single. It is a form of n modular redundancy in which three systems perform a process and that result is processed by a majority voting system to produce a single output. The faulted module can be replaced with a new module online without affecting the feedwater system operation. Triple modular redundancy tmr mastering and implementing tmr into a design greatly increases the complexity and the time it takes to build. Triple modular redundant configuration as it can be seen in figure 2, the redundancy of. The hardened design has 200% more area than the original circuit. This approach is very common in aerospace applications where the cost of failure is extremely high.
Pdf hierarchical triplemodular redundancy htmr network. The tricon appears to the user as one set of hardware, not three, allowing one control program for the application logic to be developed and. Assuming that the voting circuits v do not fail, the two configurations have identical reliability. However, one of the main challenges in achieving 100%. This is the venue of triple modular redundancy in oil, gas, energy, and chemicals. There are similar sounding terms like, tri or triple redundant, used in industry to describe other sts products but they simply do not yield the same, high level of reliability. Aikofahi hereby grant permission to the wallace memorial library of the rochester institute of technologyto reproduce mythesis in whole or in part. This unique qmr technology, based on a high level of selftesting and diagnostics, has proven that qmr is the best. Triple modular redundancy tmr has been widely used in highly reliable applications. Any reproduction will not be for commercial use or profit. In computing, triple modular redundancy, sometimes called triple mode redundancy, tmr is a faulttolerant form of n modular redundancy, in which three systems perform a process and that result is processed by a majorityvoting system to produce a single output. In computing, triple modular redundancy, sometimes called triplemode redundancy, tmr is a. Abstractthe jim bridger power plant, located near rock springs, wyoming, is a minemouth, coalfired generation station jointly owned by pacificorp and idaho power company. A microblaze tmr subsystem is of fault tolerant fail safe ftfs type, which means that it continues to work without degradation after the first failure ft and will detect a second failure fs.
The 2300d hics is built on the same advanced technology as 2300t, for a dual redundant solution. Fault tolerance is a high performance system and they have ability of system to continue errorfree operation in presence of unexpected fault. A triple modular redundant digital system for feedwater control and safety application in nuclear power plants 6 the built. With this design, system failures switches, transducers. In this paper, a simple probabilistic model was proposed for analysis of fault masking performance of hierarchical tmr networks. Implementing single source redundant clock trees in triple modular redundant synchronous architectures. If these triply redundant modules are now reconnected to assemble an entire triple modular redundant tmr.
There are different technologies that we will analyze in the future. Hierarchical triplemodular redundancy htmr network. Tmr triple modular redundant, qmr quadruple modular redundant, fmr flexible modular redundancy, xmr, etc. Hierarchical application of triplemodular redundancy tmr increases fault tolerance of digital integrated circuit ic.
So, for example, two processors compute the same correct result and the third processor is. A new scheme for implementing highly reliable digital systems is proposed. A commonly known method for seu mitigation is triple module redundancy tmr with voting. It is a form of nmodular redundancy in which three systems perform a process and that result is processed by a majority voting system to produce a single output. Triple modular redundancy tmr scheme in the fpga proceedings of the design, automation and test in europe conference and exhibition date05. In this paper, we concerned with the triple modular redundancy tmr for an onboard computer with aerospace application. Verification of triple modular redundancy tmr insertion for. Design and implementation of triple modular redundant system. For traditional tmr, this means that state machines have to be reset. Triple modular redundancy tmr uses three functionally equivalent units to provide redundant backup.
Quadruple modular redundant technology for safety systems honeywells quadruple modular redundant qmr technology with award winning 2oo4d architecture sets the standard for how safety instrumented systems should be designed. This document discusses the use of triple modular redundancy tmr for the protection of combinatorial and sequential logic in reprogrammable logic devices. A new voter design for triple modular redundant systems redundancy techniques are commonly used to design dependable systems to ensure high reliability, availability. Single event upsets seu, metastability, clock domain crossing cdc field programmable gate arrays fpga, triple modular redundancy tmr created date. Triple modular redundant system is implemented by using three single board computers as onboard data handling obdh connected with each other through passive switch as follows. Localized triple modular redundancy ltmr redundant data path. For the highest level of integrity and availability, the 2300t triple modular redundant system features voting with triple, dual or common io, as required. Selfchecked, lock step processor pairs us20020046365a1 en 20000623. Triple modular redundant, qmr quadruple modular redundant, fmr flexible modular. Reduced triple modular redundancy for tolerating seus in sram.
If any one of the three systems fails, the other two systems can correct and mask. Reliability analysis of triple modular redundancy system. Us6141769a triple modular redundant computer system and. Berg at radiation effects on components and systems radecs conference, bremen, germany, september 1923, 2016. On the optimal design of triple modular redundancy logic. Fpga system and how it will be used to synchronize the processors. It is designed to provide maximum safety and system availability. Triple modular redundant system testing is done by simulating data transmission between onboard computer and between onboard computer and gs using dummy data. How triplemodular redundancy works the t ricon digital systems triplemodular redundant architecture employs three isolated, parallel control systems and extensive diagnostics integrated into one system. Tmr defend the fpga circuit by creating three copies of a circuit. Voting logic vl is an important component of triple modular redundant tmr and nmodular redundant nmr systems.
If these triply redundant modules are now reconnected to assemble an entire triplemodularredundant tmr. Each node is communicatively coupled to two neighbor nodes and to two skip nodes using th. Hierarchical application of triple modular redundancy tmr increases fault tolerance of digital integrated circuit ic. Figure 1 hardware design these components are integrated to form a system. Tmr r3,0 3 modules, 0 spares identical modules synchronized to the level of being able to compare and vote on the outputs usually means preplanned, lockstep comparisions. Find out information about tripple modular redundancy. Deliverable to nasa electronic parts and packaging nepp program to be published on nepp. Triple modular redundancy layerzero power systems, inc. Redundant system basic concepts national instruments. This mitigation scheme uses three identical logic circuits. The method is often referred to as triple modular redundancy tmr.
The classic n modular redundant example is triple modular redundant. The trusted tmr processor is a fault tolerant design based on a triple modular redundant tmr architecture operating in a lockstep configuration. Triple modular redundancy to achieve see tolerance. The approach is called functional triple modular redundancy ftmr. So in case you have three of these processors such a the system called a triple modular redundant system, three processors, a single voter. A technique known as selective triple modular redundancy stmr is proposed in 12 that employs partial redundancy to introduce seu immunity. Redundancy is a technique to improve the reliability and availability of a system.
Imagine you have an embedded system which you want to perform very reliably. While dual redundant is the simplest redundant form for reliable systems, triple modular redundancy is the most used one. Estimation the failure rate and reliability of the triple. A number of voting logic designs are presented in this paper. Triguard pc1 and pc2 preconfigured safety systems fault. Error reduction rate per redundant module for the second. The 2300d hics is built on the same advanced technology as 2300t, for a dualredundant solution. Verification of triple modular redundancy tmr insertion. Pdf layout design and simulation of fault tolerant triple modular. The design profile, diagnosability and reliability calculation of a word voter for tmr system is presented. Reliability analysis of triple modular redundancy system with.
Triple modular redundant tmr architecture the triguard tmr fault tolerant safety control system gives users the maximum level of fault tolerance, reliability and availability in excess of 99. The voting solution uses advanced diagnostics to assist in results. Pdf a fault tolerant voter circuit for triple modular redundant. Triple modular redundancy using fault tolerant technique. The company concludes that while distributed control systems will continue to dominate process control and plcsupervisory control and data acquisition solutions offer an alternative approach, they both require a compromise. Triple modular redundancy tmr mastering and implementing tmr into a design greatly increases the complexity and the time it takes to build and debug a system the xilinx tmrtool solution works seamlessly with any hdl and synthesis tool to automatically build triple modular redundancy into a xilinx fpga based design. The use of triplemodular redundancy to improve computer. Efficient triple modular redundancy on a braided ring. The classic nmodular redundant example is triple modular redundant.
N2 technology scaling has increased the susceptibility of integrated circuits ics to experience an incorrect signal soft error. Mar 05, 2019 triple modular redundancy triple modular redundancy tmr uses three functionally equivalent units to provide redundant backup. Performance improvements obtained by second order tmr network were theoretically compared with first order tmr network. Tripple modular redundancy article about tripple modular. Pdf a fault tolerant voter circuit for triple modular. On the optimal design of triple modular redundancy logic for.
Various scenarios that simulate the failure of onboard computer on triple modular redundant system has been tested. If any one of the three systems fails, the other two systems can correct and mask the fault. Design and implementation of triple modular redundant. Reduced triple modular redundancy for tolerating seus in. A fault tolerant voter circuit for triple modular redundant. Each module communicates with each other through passive switch. Quadruple modular redundant technology for safety systems. Triple modular redundant computer system and associated method us6233702b1 en 19921217.
Trusted safety system triple modular redundant controller trusted system the trusted solution features a triple modular redundant tmr controller. In the proposed architecture, an onboard computer is designed based on triple modular redundancy tmr. Onboard computer, triple modular redundancy, reliability. The design profile, diagnosability and reliability calculation of a. A form of redundancy in which the original computer unit is triplicated and each of the three independent units feeds into a majority voter, which outputs. Pdf on jan 1, 2017, mohammed hadifur rahman and others published a fault tolerant voter circuit for triple modular redundant system find, read and cite all the research you need on researchgate. A dual triple modular redundant case study dean miller, pacificorp robert schloss, scott manson, sai raghupathula, and trent maier, schweitzer engineering laboratories, inc. T1 muller celement as majority gate for selfcorrecting triple modular redundant logic. Reliability analysis of triple modular redundancy system with spare i khalid a. The use of triplemodular redundancy to improve computer reliability pdf. Find the manuals gfk0787b genius modular redundancy flexible triple at pdf supply. Muller celement as majority gate for selfcorrecting.
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