Frame Relay - for Faster and More Efficient Data Communications ...

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Computerised System for QualityInspection in Optical-Fibre CableProductionGoran Nilsson and Solweig ViklundIn order to meet the market's increasingly stringent quality requirements - thosespecified in SS-ISO 9001, for example - Ericsson Cables AB in Hudiksvall, Sweden,has developed a computerised system for quality inspection in optical-fibre cableproduction. The system, called Dehlfi, has been in operation at the Hudiksvall factorysince 1988; another version has been used at Ericsson Cables' Spanish factory sinceits inauguration in July, 1991.The authors describe the system's design, functions and field of application.optical cablesoptical fibresquality controlinspectionstatistical process controlFig. 1Workplaces, terminals and test stations in theDehlfi systemQuality is a concept of vital importance toEricsson Cables. For a product to be improvedand optimised, its characteristicsmust be known. Knowledge of a product'squality is largely a matter of information -in design, sales and administration - andthis information must be easy to understandand make use of.A considerable number of parameters areneeded in the design and manufacture ofoptical fibre and cable. Large amounts ofmeasurement data have to be presentedin an attractive and comprehensible way -even to our customers. To achieve ourquality objectives we must have a systemthat can receive, store, process andpresent the necessary information. That iswhy Ericsson Cables has developed acomputerised system called Dehlfi (Databaseat Ericsson Hudiksvall for optical Fibreand cable).Some requirements have been given toppriority in the development of the system:- data must admit of being automaticallyentered and stored in the database- the database must be user-friendly andeasy to modify- the database must allow the use of complexrelations- printouts - especially those in the formof customer documents- must be of highquality.The manufacture of fibre and cable is describedin References 1 and 2.System descriptionDatabaseThe core of Dehlfi is a minicomputer. It isan HP 9000/835S, with RISC architectureERICSSON REVIEW No. 1-2, 1992
13GORAN NILSSONSOLWEIG VIKLUNDEricsson Cables AB(Reduced Instruction Set Computing), capableof performing 14 million instructionsper second (14 MIPS). It has an 8 Mbyteprimary memory and uses two hard disksof 571 and 670 Mbyte respectively. Twomagnetic tape stations are provided forbackup copying.The HP machine uses a UNIX operatingsystem. The database is developed in HPAllbase/4GL, which is a special databaselanguage, and has ISAM data files (IndexSequential Access Method). A number ofexternal routines are written in the two programminglanguages C and Pascal.Fibre-optic networkA star-shaped network connects the minicomputerto terminals, test stations and otherequipment, Fig. 1. Cable designers,system developers at the technical departmentand operators at the manufacturingand quality inspection departmentscan access the system via this network. In1991,12 test stations, 10 terminals and variousPCs and printers were connected tothe network.The network is made up of fibre-optic modemsand fibre-optic multimode cables,and designed according to ElA's standardRS 232 (CCITT V24/V28).The units of a test station are interconnectedvia the instrument bus HP-IB (Hewlett-Packard Interface Bus), by other instrumentmanufacturers called GPIB (GeneralPurpose Interface Bus). This is a standardised,general-purpose bus which connectsone or more test instruments to acontrol unit, thus forming a computer-controlledtest system.The communication routines are written inHP Basic, and data is transferred in theform of text sequences in ASCII code(American National Standard Code for InformationInterchange). This is not the fastestcommunication protocol available, butthe transfer time is insignificant in comparisonwith the test time.Test stationsA test station is equipped with a test instrument;for example, an OTDR (Optical TimeDomain Reflectometer) and the associatedcomputer HP 9000/332, a printer and aplotter, Fig. 2. Each test station has a specifictest program in HP Basic. The menucontrolledtest program instructs the operatorand reads the instrument. A teststation may either communicate directlywith the database or operate in standalonemode.User interfacesThe Dehlfi system has menu-based userinterfaces. Each operator category has aseparate, tailor-made set of menus, andeach operator has a unique password.Personal computers have Windows userinterfaces, Fig. 3.The introduction of Dehlfi meant considerablesaving of labour, for one thing becausethe system eliminates the time-consumingand monotonous manual recordingof test data at terminals.Fig. 2Example of test station equipmentPrinterComputerDiskette driveTest instrumentHP ThinkjetHP 9000/332HP 9122OTDRERICSSON REVIEW No. 1-2,1992
Page 1: ERICSSONREVIEW1-21992Frame Relay -
Page 4 and 5: ERICSSON REVIEWBO HEDFORSPublisher
Page 6 and 7: 4Fig. 2Distributed computer environ
Page 8 and 9: Fig. 7A company's data network shou
Page 10 and 11: 8Fig. 11The frame format used for F
Page 12 and 13: 10er (DE, Fig. 12) should be set to
Page 16 and 17: Box 1Code39, the first alphanumeric
Page 18 and 19: 16Fig. 6Cable attenuation test at E
Page 20 and 21: 18Fig. 9Installing the Dehlfi syste
Page 22 and 23: Human Factors - A Key to ImprovedQu
Page 24 and 25: 221 Use the user's model2 Introduce
Page 26 and 27: 24Fig. 5Advanced Human Factors desi
Page 28 and 29: Fig. 7User interface for PBX attend
Page 30 and 31: Cell-voltage EqualisersSeries BMP 1
Page 32 and 33: 30Box1CELL-VOLTAGE EQUALISER BMP 16
Page 34 and 35: 32age, the faulty cell or the entir
Page 36 and 37: In Search of Managed ObjectsWalter
Page 38 and 39: Fig. 4The telecommunication network
Page 40 and 41: Fig. 6Functional Model illustrating
Page 42 and 43: 40Fig. 9Combination of layering and
Page 44 and 45: 42Table 2Relationship between Funct
Page 46 and 47: 44No1PPI2PPI3SLTTransport Function(
Page 48 and 49: 46Table 4SDH functions, Resources a
Page 50 and 51: The Managed Objects and their prope
Page 52 and 53: 50Fig. 21Information Model of PDH d
Page 54 and 55: Fig. 25Information Model of SDH mul
Page 56 and 57: 54Table 5Cross-connect functions, R
Page 58: Fig. 32, leftCross-connect Fragment

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