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1. Length Type Float Float S text Text S text Float Float Float Float Float Float Float Description Fix temperature Delta temperature Environment Manual L source description Switch of Lup definition method L calculated L manually defined by user L from FRACAS L allocated Number of cycles 1000 Hours Field factor L allocation weight complexity Notes If both Fix temperature and Delta temperature fields are defined then Fix temperature will be used If both Fix temperature and Delta temperature fields are defined then Fix temperature will be used All acceptable ENV values are listed in Section 2 of this Appendix The following values are acceptable CA L Calculated MA L manually defined by user FR L from FRACAS AL L allocated Appendix D Maintainability Data Component Import Formats 613 Field name MNlorpr MNlorpl MNmswitch MNmctcal MNmctman MNmctall MNmmhcal MNmmhman MNmstempl 2 Length Type S text S text S text Float Float Float Float Float Float Description Level of repair Level of replace MCT amp MMH source switch CA MCT amp MMH Calculated MA MCT amp MMH Manual L MCT Allocated MCT Calculated MCT manually defined by user MCT Allocated MMH Calculated MMH manually defined by user Maintainability allocation weight Misce
2. Description ICONR LFDI LFTR HFDI HFTR OPTE CIND PWBD QCRY FUSE Fa KK TN EE Device type style Technology Package Ouality level Pins Bits Gates Transistors Theta je C W T junction max C Power rated dissip W Voltage rated VI Current rated A Application Suffix for resistance Resistance Suffix for capacitance Capacitance HFTR Matching HFTR Metalization OPTE Logic exists characters channels 626 RAM Commander User s Guide Max rated temperature EEPROM Subtype EEPROM Error Cor Years of production Maturity year Manufacturin g year E Manuf process VHSIC Die Area cm VHSIC Feature Size micr VHSIC Voltage Range V Appendix F Library Import File Abbreviations 627 Description Temper 2 C SRAM Subtype GAAS Subtype Fragility Internal structure Q Contact form Evaluation foi CNET active contacts keys touches cont interrupteurs cont inverseurs Protection type Courant for CNET Material Contact size Surface Largeur domin de pistos layers holes by wave holes by hand wires Frequency 628 RAM Commander User s Guide Appendix G Reliability Growth Modeling RAM Commander s reliability growth module is the Duane method as described in MIL STD 1635 In this model
3. MMH MA ring MMH cu MMH verj MMA sr J Mz 1 lt H where MMHprep average preparation MMH Z z average fault isolation MMH ss S S ZEE Z Z BEB a 8 average disassembly reassembly MMH average MMH of remove replace Interchange MM average calibration MMH MM average verification MMH MMHsz average start up MMH N number of replaceable items on the next lower level of the product tree failure rate of the jth replaceable item S ambiguity factor The value of the ambiguity factor S is used in calculating the MTTR for an assembly Appendix H Maintainability Prediction Modeling 635 Maintainability Allocation Maintainability allocation for each ith child of the current item is computed according to the formula L son Oty son Mct son MTTR item Wy on Sp EE on K HUGA M i son son where Mct son allocated Mct of ith child Wu weighing factor for maintainability allocation Qty quantity of identical lower level items L son failure rate of ith child 636 RAM Commander User s Guide Appendix I Reliability Block Diagram Computation Formulae One of the modeling scenarios that can be implemented in RAM Commander s RBD module is K out of N redundancy with or without repair Appendix Reliability Block Diagrams and Computational Formulas 637 K out of N Without Repair The formulas in the following table are used to compute
4. 100 O lt N Number of items in the i ambiguity group Xo N5 0 Appendix H Maintainability Prediction Modeling 633 It is assumed that failure is isolated to an entire group of 0 lt N lt 99 for i 1 5 parts The probability that the fault will be isolated for Ns parts is X 100 You can use up to 5 groups i e i lt 5 The probability of the highest one must be equal to 100 Furthermore the inequality X1 lt X2 lt X3 lt X4 lt X5 must hold Maximum Corrective Maintenance Time The Maximum Corrective Maintenance Time for the th percentile Mctx 0 is the value of corrective maintenance time below which 6 percent of all maintenance actions are expected to be completed Mctmax 9 exp log MTTR 60 mal where N N gt log Mct I log Mct N i l i l N 1 O Met Mean Maintenance Man hours per Maintenance Action Component level K MMH MA gt MMH i l i MP Ms Il En where 634 RAM Commander User s Guide MMH Mean maintenance man hours required for the ith maintenance task preparation fault isolation disassembly reassembly etc Ti average time to perform the ith maintenance task see Mct definition above MP Manpower reguired for the ith maintenance task K number of maintenance tasks reguired preparation fault isolation disassembly reassembly etc Assembly Level N SA IMME prep MMH go S MMH p p MMH AS j l
5. Import Formats 611 Description Spare Part Turnaround time Spare Part Condemnation Rate Spare Part Minimal Qty Spare Part Maximal Qty SMR Field that should be ignored n Number of chars to be ignored equal to 1 by default This field is used to ignore columns of text file and or make blanks between fields Max width 150 chars Operating Data Field Length Type Description Notes name OPftemp 9 Float Fix temperature If both Fix temperature and Delta temperature fields are defined then Fix temperature will be used OPdtemp 9 Float Delta temperature If both Fix temperature and Delta temperature fields are defined then Fix temperature will be used OPenv 3 S text Environment All acceptable ENV values are listed in Section 2 of this Appendix OPmldser 31 Text Manual LAMBADA L source description OPlswitc 2 S text Switch of Lup definition The following values are acceptable CA L Calculated h method MA L manually defined by user FR L from FRACAS AL L allocated OPlcal 9 Float L calculated OPlman 9 Float L manually defined by user OPlfra 9 Float L from FRACAS OPlall 9 Float L allocated OPdc 9 Float Duty cycle OPkfld 9 Float Field factor OPlcmpl 9 Float L allocation weight complexity 612 RAM Commander User s Guide Non operating Data Field name NOftemp NOdtemp NOenv NOmidscr NOlswitch NOlcal NOlman NOlfra NOlall NOnc NOkfld NOlcmpl 9 31
6. MTTF and reliability for various redundant item loads and without item repair Source Data Models Load of redundant vahi iens MTTF Reliability N K 100 FAK eu ae N N K i us io K i N K 1 er i to K 1 iz K i N K 1 N K K At 1 0 e K t 0 i AK d i A N K 0 lt v 100 lt 100 1 SK 1 TE on A i K vi i 0 J e EDA to v N K K vi 638 RAM Commander User s Guide K out of N With Repair 44772 u MTBF The formulas in the following table are used to compute MTBF and reliability for various redundant item loads with item repair Source Data Calculations Models Load of Steady State Repair redundant MTBF exact value Mission Reliability over time Availability z ieme to approximate value approximate value Unre 100 s N s N N Pa stricted 1 M K 2 i 7 re AS EN Y a N K 1 2 exp PK TTSS NA C S On pe S s sy Re 100 1 N K S 1 _ K KI N N K 1 stricted A oo mee N S i NEES 1 on ved CRD i 1 2 rales Al 22 4d 0 i Priks 3 m N 2 N K 1 i 0 1 Mx N K D i ep KT AFE Ky stricte Ki it J Ky iso i 1 Ky N K 1 Appendix Reliability Block Diagrams and Computational Formulas 639 K out of N with Repair Source Data Calculations Models MTBF exact value Mission Reliability over time Steady State to approximate value Availability approximate value Re 0 1 1 RA H N K HUK KINK Ky KA
7. The numbers in the column Dialog boxes with this field on the next page refer to the table below Dialog box name Number Tree Level Item Parameters 1 Tree General Tree Operating reliability Tree Nonoperating reliability Tree Maintainability Ru A N Tree Miscellaneous 594 RAM Commander User s Guide Tree Data Screens fields and explanations Field name Family Item code Description Item family Item code See list of item Ref Des Reference Designator Part name Item part name Quantity in current assembly Quantity Environment Cur ENV Item environment Current environment set to parent s environment if in Environment field Ifuser defined you must fill in Method of Lp Method the Method field Required if Method of Lp or Method of Mct are user defined Source for failure rate No prompt Dialog boxes Values or with this field field type 2 4 i ELECTRONIC MECHANICAL EL MECH 2 4 codes on page 600 1 6 1 4 2 5 1 3 4 See list of environment codes on page 603 1 3 4 Set by RAM Commander 3 4 Default User defined 3 4 See list of prediction methods on page 601 3 4 Calculated User defined From FRACAS Allocated Appendix B Data Input Screens and Fields 595 su Dialog boxes Values or migra name Descriptien with this field field type No prompt Type of ambient temperature If 1 3 4 Fixed Temp Fixed Temp the item s te
8. the tested mean time between failure MTBF is proportional to T where T is the cumulative operating test time and a is the growth rate index On a log log plot the growth regression line is linear with slope a The cumulative mean time before failure MTBF is normally measured during testing and then divided by 1 la to convert it to the current instantaneous mean time before failure MTBF MTBF is then plotted parallel to the MTBF at an offset of 1 1 a The test time at which this line reaches the required MTBF is the expected duration of the reliability growth test RAM Commander uses Bootstrap a new statistical technology that enables the user to calculate accurate confidence intervals for the main parameters of the Duane model by obtaining a large number of samples Details of this method have been published in the paper Bootstrap Technology for RAM Analysis Z Bluvband and L Peshes Proceedings of the Symposium on New Directions in Military Reliability Availability and Maintainability RAM Analysis Maryland USA 1993 Appendix G Reliability Growth Modeling 629 Derivation of Model Equations According to the Duane formulation F KH E where As cumulative failure rate H total test hours F failure during H hours K condition dependent coefficient a growth rate The original mathematical model was expressed in terms of cumulative failure rate However since equipment reliability is gene
9. ty Ky stricted K4 KU KT LKK CN K Dt Ky s y i s yi i Unre 0 lt v 100 lt 100 pee ea ee l SC HIK LN K L 0 Oo ess S st 0 st Lost stricted Ab HK4 N K 1 n v S SIKAN K N K 1 rel r 1 Sy II K N K 1 nv Sy II K N K 1 nV gt T W K I r v Yy N K 1 r v Weed Re 0 lt v 100 lt 100 INK j ep S SO ra 1h N Kain stricted s 0 78 K N K 1 r v 59 yp TK N K 1 ny p r l rel 640 RAM Commander User s Guide Appendix Reliability Distributions The following table lists the probability distributions and associated reliability functions used in computing reliability Distribution Exponential Weibull Normal Log normal Erlang Uniform Reliability Function R 1 FO A t e 4 C fdr far e poe i o i b t b a Probability Density Function f t Aer batt te 5 1 e 20 OV27 1 E a Ot 2n JE le x 1 fora lt t lt b a Reliability Block Diagrams and Computational Formulas 641 Parameters 1 MTBF a gt 0 b gt 0 gt 0 lt U lt o gt 0 lt U lt 0 o gt 0 gt 0 K positive integer O lt a lt b 642 RAM Commander User s Guide
10. 5 C GF Ground Fixed Conditions less than ideal with some environmental stress and limited maintenance Typical applications are manholes remote terminals and areas in subscribed premises subject to shock and vibration or temperature and atmospheric variations GM Ground Mobile Conditions more severe than for Ground fixed mostly for shock and vibration There is less maintenance attention and equipment is susceptible to operator abuse Typical applications are mobile telephones portable operating equipment and test equipment Bellcore Issue 5 GB Ground Fixed Nearly zero environmental stress with optimum engineering operation and maintenance Typical applications are central office environmentally controlled vaults environmentally controlled remote shelters and environmentally controlled customer premise areas GF Ground Fixed Some environmental stress with limited maintenance Typical applications are manholes poles remote terminals customer premise areas subject to shock vibration temperature or atmospheric variations GM Ground Mobile Conditions more severe than GF mostly for shock and vibration More maintenance limited and susceptible to operator abuse Typical applications are mobile telephones portable operating equipment and test equipment 608 RAM Commander User s Guide Bellcore Issue 6 Telcordia Issue 1 GB Ground Fixed Nearly zero environmental stress with optimum engineering operation and mainte
11. Appendix A Glossary of Field Abbreviations 591 Appendix A Glossary of Field Abbreviations Field Complia FIT FR L La Lf Lm Lp Ma Mct MMH MTBCF MTBF MTTR NPRD PD PTB R t Definition weighing complexity factor in reliability allocation for La failure rate in units of 10 failure rate failure rate measure of reliability allocated failure rate field failure rate imported from FRACAS manually entered failure rate predicted calculated failure rate maintenance action maintenance corrective time mean maintenance man hours mean time between critical failures mean time between failures mean time to repair non electronic part reliability data power dissipation product tree building reliability as a function of time 592 RAM Commander User s Guide Field RBD RG RP RP component data RTF S TAT VSR Xi Definition reliability block diagram reliability growth reliability prediction RP related data influenced by the reliability prediction model Processor RAM Commander file format used for importing data from ASCII files ambiguity factor average number of iterations required to correct a fault turn around time voltage stress ratio weighing complexity factor for maintainability allocation probability of fault isolation to N replaceable items Appendix B Data Input Screens and Fields 593 Appendix B Tree Data Input Screens and Fields
12. LECOM HRD5 CNET RDF93 rev 02 95 GJB299 Part Count GJB299 Part Stress HRDS TELECOMM ITALTEL IRPH93 MIL 217E 1 P stress MIL 217F 1 P count MIL 217F 1 P stress MIL 217F 2 P count MIL 217F 2 P stress NPRD 95 NSWC 92L01 Mechanics Siemens SN29500 1 Table Packed to Box Telcordia Issue 1 UTE C 80 810 602 RAM Commander User s Guide Non operating Methods MIL 217E 1 draft NPRD 95 RADC TR 85 91 Table Packed to Box Reliability Toolkit 1995 Maintainability Methods MIL STD 472 Procedure 5 Method A Appendix C Methods and Environments 603 Defined Environments for Selected Operating Methods A British Environ MIL 217FN1 Bellcore Bellcore6 Italtel HRD5 CNET RADC TR 85 91 MIL 217EI ENZ Alcatel ISSue5 Telcordia 1 IRPH93 Telecomm RDF 93 82 MIL 217E 1 draft Airborne Airborne Airborne Inhabited Inhabited Inhabited Attack Fighter Airborne Airborne Inhabited Inhabited Bomber Cargo Airborne Airborne i Airborne Inhabited Moderate Inhabited Inhabited Fighter Fighter Fighter Airborne Airborne Inhabited Inhabited Trainer Cargo Airborne Ground Airborne Rotary Rotary Mobile Winged Winged Violence GM2 AIC i Airborne Airborne i Airborne ited Inhabited commercial non i i Inhabited Cargo Cargo AC stationary used Temperature controlled 604 RAM Commander User s Guide Environ MIL 217FN1 Bellcore Bellcore 6 Italtel prin
13. WIT TUBE UNDF Definition Low frequency diode Low frequency transistor Laser gas Laser Semiconductor device Laser solid state Meter Miscellaneous Optoelectronic device Potentiometer Printed wiring board Quartz Crystal Relay can be tree hierarchy item Resistor Rotating device Surface acoustic wave Substrate tree hierarchy item Switch Tube Undefined tree hierarchy item Appendix E Import File Abbreviations 617 Hierarchy Item Codes UNDF FLTR RELY Hybrid are defined as follows HYBR then SUBS on next lower level and then components on the next lower level is used for hierarchy item or item that represents a purchased part with User manually defined failure rate if they have no children they are calculated as usual if one of them has children it is considered to be an assembly and gets children s failure rates 618 RAM Commander User s Guide Environment Codes Abbreviation AIA AIB AIC AIF AIT ARW GMS MFA MFF ML MP NH Definition Airborne Inhabited Attack Airborne Inhabited Bomber Airborne Inhabited Cargo Airborne Inhabited Fighter Airborne Inhabited Trainer Airborne Rotary Winged Airborne UnInhabited Attack Airborne UnInhabited Bomber Airborne UnInhabited Cargo Airborne UnInhabited Fighter Airborne UnInhabited Trainer Cannon Launch Ground Benign Ground Fix Ground Mobile Ground Missile Silos Airbreathing Missi
14. aintenance Time e Mean Maintenance Man hours per Maintenance Action MMH MA Maintenance Corrective Time The formula for computing Mct is Mctj TPREPj TISOj TDISj TR Rj TREASj TCALj TVERj TSTj where Met average maintenance corrective or repair time for the jth replaceable item TPREP average preparation time for the jth replaceable item Tisoj average fault isolation time for the jth replaceable item Tous average disassembly time for the jth replaceable item Trej average time to remove replace interchange the jth replaceable item 632 RAM Commander User s Guide TREAS average reassembly time for the jth replaceable item TcALj average calibration time for the jth replaceable item Tverj average verification time for the jth replaceable item Tstj average time of start up for the jth replaceable item Mean Time to Repair The formula for computing MTTR is N gt 2 LTprer Tisoj S Tpas Ters Treas Tearj Tverj Ten MTTR tha r Il where N number of replaceable items on the next lower level of the product tree failure rate of the jth replaceable item Ambiguity factor as computed below Ambiguity Factor The ambiguity factor is the average number of iterations required to correct a fault and is computed as 1 Z N N 1 S peas Oa sa A 100 2 i i 1 2 where Xi probability of fault isolation to N replaceable items X lt X lt X3 lt X4 lt
15. ed to weather conditions and immersed in salt water AIF Typical conditions in fighter which can be occupied by pilots Without high temperature high pressure and violent strike and vibration AUF Severe conditions of high temperature high pressure and violent strike and vibration etc such as equipment compartment and bomb bay in fuselage tail wing of fighter AIC Typical conditions in cargo compartments which can be occupied by an aircrew AUC Environmentally uncontrolled areas which cannot be inhabited by an aircrew during flight SF Earth orbital Approaches benign ground conditions Vehicle neither under powered flight nor in atmospheric reentry such as installing environment of electronic equipment in satellites ML Severe conditions related to missile launch solid rocket motor propulsion powered flight space vehicle boost into orbit and vehicle re entry and landing by parachute such as noise vibration strike and other severe conditions 610 RAM Commander User s Guide Appendix D Component Import Formats The following tables list by screen name the various input fields used in import files Tree General Field name Length Type TRrefdes TRdepth TRicode TRaty TRgname TRcatnum TRmilnum TRpN FindName TRdscr TRrem TRManuf TRlen 10 2 21 31 31 31 31 41 21 10 19 Text Int S text Int Text Text Text Text Text Text Text Text Tex
16. failure rate Computed failure rate value of current item Check status Calculation status Item catalog number Item military number Item generic name used in library searches for component Item description Item remark Number of on off cycles per 1000 hrs Dialog boxes with this field 3 3 4 3 4 3 4 3 5 1 2 Values or field type Set by RAM Commander Set by RAM Commander no status Err Error Warn Warning O K OK Set by RAM Commander no status Err Error Warn Warning O K OK U U U C C ser defined string ser defined string ser defined string ser defined string ser defined string Field name Cur Nc Method of Mct calculation No prompt Mct c Mct m Mct a Complexity for Mct a MLH c MLH m False Alarm Rate Appendix B Data Input Screens and Fields 597 Description Current number of on off cycles per 1000 hrs set to parent s Nc if in Nc field Ifuser defined you must fill in the Method field Maintenance corrective time source flag Calculated maintenance corrective time calculated User defined maintenance corrective time Allocated maintenance corrective time Complexity for allocated Mct Calculated mean labour hour User defined mean labour hour False alarm rate Level of replace Level of replace Dialog boxes Values or with this field field type 1 4 Set by RAM Commander 5 Defaul
17. ish RADC TR 85 91 MIL 217E1 N I 5 E Telecom ment FN2 Alcatel ssue Telcordia 1 IRPH93 MIL 217E 1 draft AUA Airborne Airborne Airborne ninhabited Uninhabited ninhabited Attack AUB Airborne ninhabited Bomber Airborne Airborne Airborne Severe Uninhabited Uninhabited Cargo Cargo Airborne Airborne Airborne Airborne 7 S Uninhabited Uninhabited Extremely Uninhabited Uninhabited Fighter Fighter Severe Fighter Fighter Airborne Airborne Airborne Uninhabited Uninhabited Uninhabited Trainer Cargo Trainer Ground Ground Ground Fixed i Stationary Benign Controlled Controlled GF Ground Ground Fixed Ground Ground Ground Non i Fixed weather Uncontrolled Uncontrolled protected Appendix C Bellcore Issue 5 Environ MIL 217E1 MIL 217FN1 ment FN2 Alcatel j GMS Ground Ground Mobile both vehicular MFF Missile Missile Flight Free Flight ML Missile Missile Launch Launch Ground Unsheltered Methods and Environments 605 British 1 1105 CNET Telecom HRD4 Telecomm RDF 93 RADC TR 85 91 MIL 217E 1 draft Italtel IRPH93 Bellcore 6 Telcordia 1 GJB299 Ground Mobile installations Stationary Smooth Protected GM1 Ground Mobile both vehicular Ground Moign Weather protected Non temperature controlled Ground Missile Silo Airbreathing Missile Flight Missile Free Flight Missile Lau
18. ld field type Item weight Item weight in kilograms 6 User defined floating point value Item volume Item volume 6 User defined floating point value Power Power consumption in watts 6 User defined consumption floating point value Current Current consumption in Amperes 6 User defined consumption floating point value Burn in Burn in temperature in C 1 6 User defined Temperature C floating point value Burn in Time Burn in time in hours 1 6 User defined positive integer PI FY Result from burn in calculation First 6 Set by RAM year multiplier ratio of the first year Commander failure rate to the steady state failure rate 600 RAM Commander User s Guide List of Item Codes Assembly Breaker Bubble Memory Capacitor Connection Connector Crystal Filter Fuse HF Diode HF Transistor Hybrid IC Analog IC Digital IC Memory Inductive Lamp Laser Diode Laser Gas Laser Solid LF Diode LF Transistor Meter Miscellaneous Optoelectronic Potentiometer PWB Relay Resistor Rotating SAW Substrate Switch Tube Appendix C Methods and Environments 601 Appendix C Methods and Environments RAM Commander s data base contains data from the following operating reliability prediction methods This list is complete as of January 1 1996 ALD will continue to update its data base support as new methods are issued Operating Methods ALCATEL BELLCORE Issue 5 BELLCORE Issue 6 BRITISH TELECOM HRD4 BRITISH TE
19. le Flight Missile Free Flight Missile Launch Manpack Naval Hydrofoil Abbreviation NS NSB NU NUU SF USL Appendix E Import File Abbreviations Definition Naval Sheltered Naval Submarine Naval UnSheltered Naval Undersea UnSheltered Space Flight Undersea Launch 619 620 RAM Commander User s Guide Stress Codes Part IC memory Hf transistor memory ae digital tor tiometer citor diode poe diode eae para meters MI fs ee Mc eo S MI lt E RRR CS Ee ee ee ee eee lt 7 7 e MM M MEE RE MN 0O a E VV ewes 9 0O les Capa Switch Relay Lf Hf citor diode Pass diode es para meters Appendix E Import File Abbreviations 621 Part Il Optoelectronic Breaker Stress para Opto Bubble Conn Indu Fuse Laser SAW Lamp Filter Breaker Stress para meters electronic memory ector ctive Diode Stress para Opto Bubble Conn Indu Fuse Laser SAW Lamp Filter Breaker Stress para meters electronic memory ector ctive Diode meters 622 RAM Commander User s Guide Stress Parameter Abbreviations Abbreviation Description CAP Applied current CSR Current stress ratio CSR PDI Power dissipation PSR Power stress ratio PSR TIC Delta temperature junction to case ambient VAA Applied vo
20. llaneous Data Notes The following values are acceptable UN Unapplicable OR Organizational IN Intermediate DE Depot DI Discard i e not reparable The following values are acceptable UN Unapplicable OR Organizational IN Intermediate DE Depot Field name Length Type Description Micurency 3 S text Currency USD US dollars FF French Francs Mlprice 9 Float Item price Mlcur 9 Float Current consumption A MIpwr 9 Float Power consumption W Mlweight 9 Float Weight Kg MlIvolume 9 Float Volume M3 614 RAM Commander User s Guide Stress Information Stress 150 chars Text Stress information Example of Stress data TJC 5 VSR 0 4 Appendix E Import File Abbreviations 615 Appendix E Import File Abbreviations The following abbreviations can be used for import file field values instead of their full nomenclature that appears on screen list boxes Item Code Abbreviations Abbreviation Definition BUBM Bubble memory CAPC Capacitor CBRK Circuit breaker CIND Coil inductive device CONR Connector and IC sockets CONT Connection FLTR Filter can be tree hierarchy item FUSE Fuse HFDI High frequency diode HFTR High frequency transistor HYBR Hybrid IC tree hierarchy item ICAN IC Analog ICDI IC Digital ICME IC Memory LAMP Lamps incandescent 616 RAM Commander User s Guide Abbreviation LFDI LFTR LGAS LSEM LSOL METR MISC OPTE POTN PWBD QCRY RELY RESI ROTD SACW SUBS S
21. ltage alternative VAP Applied voltage direct VDA Applied voltage drain source VDS Voltage stress ratio drain source VSRds VGA Applied voltage gate source VGS Voltage stress ratio gate source VSRgs VSR Voltage stress ratio VSR VRA Rated Voltage VGR Rated Voltage gate source VDR Rated Voltage drain source CRA Rated Current PRA Rated Power FRA Frequency Applied FRS Frequency SR Appendix F Library Import File Abbreviations 623 Appendix F Library Import File Abbreviations and Field Names e CAPC e CIND e CONR e FUSE e HFDI e HFTR e ICAN e ICDI e ICME e LFDI e LFTR e OPTE e POTN e PWBD e OCRY e RELY e RESI e SWIT e BUBM Capacitor Coil inductive device Connector and IC sockets Fuse High frequency diode High frequency transistor IC Analog IC Digital IC Memory Low frequency diode Low frequency transistor Optoelectronic device Potentiometer Printed wiring board Quartz Crystal Relay can be tree hierarchy item Resistor Switch Bubble memory 624 RAM Commander User s Guide e CBRK e CONT e FLTR e HYBR e LAMP e LGAS e LSEM e LSOL e METR e MISC e ROTD e SACW e SUBS e TUBE Circuit breaker Connection Filter Hybrid IC Lamps incandescent Laser gas Laser Semiconductor device Laser solid state Meter Miscellaneous Rotating device Surface acoustic wave Substrate Tube Appendix F Library Import File Abbreviations Library Import File Field Names 625
22. mperature Delta Temp is equal to the value entered in the adjacent C field If Delta Temp the item s temperature is equal to the value in the adjacent C field plus the parent s temperature C Temperature in C 1 3 4 Value in C Cur Temp Actual current temperature 1 3 4 Set by RAM Commander FRp Predicted calculated failure rate 1 3 4 Set by RAM Commander FRu User defined failure rate Takes 3 4 User defined effect only if FR source is user floating point value defined see above Source of FRu Source of user defined failure rate 3 4 User defined string value FRf Failure rate from field data or from 3 4 Value of Lf FRACAS Takes effect only if FR source is FRACAS see page 594 FRa Allocated failure rate Takes effect 1 344 Value of allocated only if FR source is Allocated lambda see page 594 Complexity for Complexity factor for reliability 3 4 Value of FRa allocation This parameter is valid if complexity factor you selected Allocated failure rate Field factor Field factor multiplier for computing 3 4 item failure rate 596 RAM Commander User s Guide Field name Duty cycle Mult factor Add factor Item Failure Status Check Status Calc Catalog number Military number Generic name Description Remark Nc Description Duty cycle multiplier for computing item failure rate Multiplicative factor multiplier for computing item failure rate Additive factor multiplier for computing item
23. nance Typical applications are central office environmentally controlled vaults environmentally controlled remote shelters and environmentally controlled customer premise areas GF Ground Fixed Some environmental stress with limited maintenance Typical applications are manholes poles remote terminals customer premise areas subject to shock vibration temperature or atmospheric variations GM Ground Mobile Conditions more severe than GF mostly for shock and vibration More maintenance limited and susceptible to operator abuse Typical applications are portable and mobile telephones portable operating equipment and test equipment AIC Airborne commercial Conditions more severe than GF mostly for pressure temperature shock and vibration In addition the application is more maintenance limited than for GF Typical applications are in the passenger compartment of commercial aircraft SF Spacebased commercial Low earth orbit Conditions as for AIC but with no maintenance Typical applications are commercial communication satellites GJB299 GB Normally weather almost no mechanical stress and readily accessible to maintenance such as laboratory with temperature and humidity controlled or large ground station GMS Typical conditions in ground silo in which missiles and its assistant equipment are set GF GF1 Typical conditions in the inside of generic building or on permanent racks with good ventilation With moderate s
24. nch Partly weather protected and non weather protected Manually transport Manpack Naval Sheltered Generic NS2 Naval Hydrofoil 606 RAM Commander User s Guide Environ ment NS INaval Sheltered NSB Naval Naval Submarine Sheltered NU INaval Unsheltered Unsheltered Bellcore MIL 217FN1 MIL 217E1 Issue 5 FN2 Alcatel Naval Sheltered NUU INaval Undersea Unsheltered SF Space Space Flight Flight USL Undersea Missile Launch Launch Naval Unsheltered Bellcore 6 Telcordia 1 Spacebased commercial SC Italtel IRPH93 is HRD5 CNET Goo RADC TR 85 91 e ecom Telecomm RDF 93 MIL 217E 1 draft Naval Naval Sheltered Sheltered Benign NS1 Naval Undersea Unsheltered Ground Fixed Atrocious weather Appendix C Methods and Environments 607 Notes on Environments and Operating Methods BRITISH TELECOM HRD4 GB Ground Benign Nearly zero environmental stress with optimum conditions for operation and maintenance Typical applications are in main exchange buildings environmentally controlled remote exchanges or cabinets including Case Repeater Equipment and environmentally controlled subscribers premises The equipment is operated in a protected environment free from significant shock and vibration with the temperature of the air immediately surrounding the component not exceeding 55 C and relative humidity rarely exceeding 70 at 1
25. rally expressed in terms of MTBF the following expression is more frequently used MTBF MTBF t MTBFr required MTBF MTBF initial MTBF ti time at which initial data point is plotted preconditioning time T time at which the instantaneous MTBF of the equipment under test will reach the required MTBF Differentiating the equation with respect to time we receive Lene a is MD S l a KH 1 oh 630 RAM Commander User s Guide Thus the current instantaneous failure rate is 1 a times the cumulative failure That is the instantaneous MTBF is 1 1 a times the cumulative MTBF The instantaneous MTBF may be interpreted as the MTBF that the equipment under test would exhibit if we stopped the reliability growth and continued testing Thus on a logarithmic plot instantaneous or current status curves are straight lines displaced a fixed distance from the cumulative plot by a factor of 1 a The cumulative MTBF MTBF is normally measured during testing and then converted to the instantaneous or current MTBF MTBF by dividing by 1 a that is MTBF C MTBF gt l l a Appendix H Maintainability Prediction Modeling 631 Appendix H Maintainability Prediction Modeling This appendix presents theoretical development for five maintainability modeling techniques e Maintenance Corrective Time Mct e Mean time to repair MTTR e Ambiguity factor e Maximum Corrective M
26. t Description Reference designator Tree depth level in the Import file The first line 4 e top of the importing Sub tree must always have a depth equal to 1 Note that the RAM Commander handles up to 10 tree levels including project top Predefined shortcuts of Item codes Family type is determined by the RAM Commander due to the Item code Mechanical and Electro Mechanical item codes are moved to other families Tree hierarchy items assemblies must have the UNDEF item code If not specified or not included set to UNDEF Ouantity of item s Generic name Short library code Catalog Number Factory ID Library may be accessed through the Cross Reference option Military Number Library may be accessed through the Cross Reference option Part name Manufacture ID Library may be accessed through the Cross Reference option one ofthe four item s identifiers Generic name or Catalog Number or Military Number or Part name If one column field of an Import file includes two or more item s identifiers e g Generic names and Military Numbers then you should use this field type Upon completing the RTF import procedure you must run the Load from library option to retrieve imported data Item description Item remark Manufacturer s name Logistics Control Number Field name TRSPTTm TRSPCRat TRSPMinQ TRSPMaxQ TRSPSMR Ignore Length Type 12 12 Float Float Int Int Text Text Appendix D Component
27. t User defined 5 Calculated User defined Allocated 5 Set by RAM Commander 5 User defined floating point value 5 User defined floating point value 5 5 Set by RAM Commander 5 User defined floating point value 5 5 Inapplicable Organizational Intermediate Depot 598 RAM Commander User s Guide Field name Level of repair Description Level of repair Dialog boxes with this field 1 5 Values or field type Inapplicable Organizational Intermediate Depot Discard Ambiguity factor 1 5 Set by RAM Commander Allocated MTTR MTTRa 1 5 User defined floating point value Conf Level Mct Hrs MLH MTTR Mct max N1 N5 1 5 Confidence level Mean labour hours confidence level probability 1 5 1 5 1 5 1 5 1 5 1 5 70 75 80 85 90 95 98 99 99 5 99 9 Set by RAM Commander Set by RAM Commander Set by RAM Commander Set by RAM Commander Calculation result Mean time to repair Calculation result for a given User defined non negative integer User defined Fault isolation to N1 N5 parts with Probability of fault isolation to N1 N5 parts 1 5 integer between 0 100 User defined value Item s price in selected currency Item price Currency Currency code US FF Appendix B Data Input Screens and Fields 599 A kari Dialog boxes Values or migra name Description with this fie
28. trike and vibration Such as environment in which permanent installation radar communications facilities TV and recorder etc are installed NUU GF2 Ground conditions with poor protected facilities for weather and Underground conditions Severe conditions related to high temperature low temperature difference in temperature severe humidity mildew salt vapor and chemic gas etc GM GM1 Equipment installed on vehicles which moved smoothly With strike and vibration conditions such as special vehicle running on highroad carriage of train Appendix C Methods and Environments 609 ARW GM2 Equipment installed on tracked vehicles With violent strike and vibration conditions related to violently moving and with restricted control of ventilation temperature and humidity MP Equipment manually transported in field environment With poor maintenance conditions NSB Typical conditions in submarines NS GS1 Include sheltered or below deck conditions on surface ship which travel smoothly Unserious exposed to salt vapor and water vapor Such as air conditioning cabin of large cargo ship traveling near coastal waters and ship traveling in freshwater NH GS2 Sheltered conditions without exposed to weather conditions but often with violent strike and vibration Include sheltered or below deck conditions on surface ship NU Typical conditions in board of ship Unprotected surface ship borne often with violent strike and vibration expos

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