Kev soj ntsuam pov thawj yog ib feem tseem ceeb ntawm kev saib xyuas kev ruaj ntseg ntawm peb cov cuab yeej siv kev nyab xeeb (SIS) thiab cov tshuab ntsig txog kev nyab xeeb (xws li lub tswb tseem ceeb, hluav taws kub & roj, instrumented interlock systems, thiab lwm yam). Kev ntsuas pov thawj yog ib ntus kuaj xyuas kom pom qhov ua tsis tiav txaus ntshai, ntsuas kev nyab xeeb ntsig txog kev ua haujlwm (xws li rov pib dua, hla dhau, tswb, kuaj, phau ntawv kaw, thiab lwm yam), thiab xyuas kom lub kaw lus ua tau raws li lub tuam txhab thiab cov qauv sab nraud. Cov txiaj ntsig ntawm kev ntsuas pov thawj kuj yog ib qho kev ntsuas ntawm qhov kev ua tau zoo ntawm SIS mechanical integrity program thiab qhov kev ntseeg siab ntawm qhov system.
Cov txheej txheem kuaj pov thawj npog cov kauj ruam los ntawm kev tau txais daim ntawv tso cai, ua cov ntawv ceeb toom thiab coj lub kaw lus tawm ntawm kev pabcuam rau kev kuaj xyuas kom paub meej cov kev xeem, sau cov ntaub ntawv pov thawj thiab nws cov txiaj ntsig, muab lub kaw lus rov qab rau hauv kev pabcuam, thiab ntsuas qhov ntsuas tam sim no thiab cov ntaub ntawv pov thawj yav dhau los xeem tau.
ANSI/ISA/IEC 61511-1, Clause 16, suav nrog SIS pov thawj. ISA technical report TR84.00.03 - "Mechanical Integrity of Safety Instrumented Systems (SIS)," npog cov ntaub ntawv pov thawj thiab tam sim no nyob rau hauv kev kho nrog ib tug tshiab version yuav tawm sai sai no. ISA daim ntawv tshaj tawm kev tshaj lij TR96.05.02 - "In-situ Proof Testing of Automated Valves" tam sim no tab tom txhim kho.
UK HSE tsab ntawv ceeb toom CRR 428/2002 - "Cov ntsiab cai rau kev kuaj pov thawj ntawm kev ruaj ntseg ntsuas tshuab hauv kev lag luam tshuaj" muab cov ntaub ntawv pov thawj thiab cov tuam txhab ua haujlwm hauv UK.
Cov txheej txheem kev xeem ntawv pov thawj yog ua raws li kev soj ntsuam ntawm cov kev paub tsis txaus ntseeg rau txhua yam ntawm cov khoom hauv kev nyab xeeb ntsuas kev ua haujlwm (SIF) txoj kev mus ncig, SIF kev ua haujlwm raws li qhov system, thiab yuav ua li cas (thiab yog tias) sim rau qhov tsis ua haujlwm txaus ntshai hom. Kev txhim kho txheej txheem yuav tsum pib nyob rau hauv SIF tsim theem nrog rau kev tsim qauv, xaiv cov khoom, thiab kev txiav txim siab thaum twg thiab yuav ua li cas pov thawj. SIS cov cuab yeej muaj qhov sib txawv ntawm cov pov thawj nyuaj uas yuav tsum tau txiav txim siab hauv SIF tsim, kev ua haujlwm thiab kev saib xyuas. Piv txwv li, orifice meters thiab siab transmitters yog yooj yim rau kev ntsuam xyuas dua Coriolis huab hwm coj flowmeters, mag meters los yog los ntawm-the-air radar theem sensors. Daim ntawv thov thiab lub valve tsim kuj tuaj yeem cuam tshuam qhov kev nkag siab ntawm qhov kev ntsuas pov thawj valve kom ntseeg tau tias qhov txaus ntshai thiab qhov ua tsis tiav vim qhov kev puas tsuaj, ntsaws lossis lub sijhawm tsis ua haujlwm tsis ua rau qhov tsis ua haujlwm tseem ceeb hauv lub sijhawm xeem xaiv.
Thaum cov txheej txheem kev xeem ntawv pov thawj feem ntau yog tsim los ntawm SIF engineering theem, lawv yuav tsum tau tshuaj xyuas los ntawm qhov chaw SIS Technical Authority, Kev Ua Haujlwm thiab cov cuab yeej cuab tam uas yuav ua qhov kev sim. Kev soj ntsuam kev nyab xeeb ntawm txoj haujlwm (JSA) kuj yuav tsum ua. Nws yog ib qho tseem ceeb kom tau txais cov nroj tsuag yuav khoom ntawm qhov kev ntsuam xyuas yuav ua li cas thiab thaum twg, thiab lawv lub cev thiab kev nyab xeeb ua tau. Piv txwv li, nws tsis zoo los qhia ib feem ntawm kev kuaj mob stroke thaum Pawg Neeg Ua Haujlwm yuav tsis pom zoo ua nws. Nws kuj tau pom zoo tias cov txheej txheem kev xeem ntawv pov thawj yuav raug tshuaj xyuas los ntawm tus kws tshaj lij kev ywj pheej (SME). Qhov kev ntsuam xyuas ib txwm xav tau rau kev xeem ua haujlwm puv ntoob yog qhia hauv daim duab 1.
Daim ntawv pov thawj kev ua haujlwm puv ntoob Daim duab 1: Daim ntawv pov thawj kev ua haujlwm tag nrho rau kev ntsuas kev nyab xeeb (SIF) thiab nws cov ntsuas kev nyab xeeb (SIS) yuav tsum sau tawm lossis xa mus rau cov kauj ruam hauv ib ntus los ntawm kev npaj xeem thiab cov txheej txheem xeem rau cov ntawv ceeb toom thiab cov ntaub ntawv. .
Daim duab 1: Daim ntawv pov thawj kev ua haujlwm tag nrho rau kev ntsuas kev nyab xeeb (SIF) thiab nws cov cuab yeej ntsuas kev nyab xeeb (SIS) yuav tsum sau tawm lossis xa mus rau cov kauj ruam hauv ib ntus los ntawm kev npaj xeem thiab cov txheej txheem xeem rau cov ntawv ceeb toom thiab cov ntaub ntawv.
Kev ntsuam xyuas pov thawj yog ib qho kev npaj kho mob uas yuav tsum tau ua los ntawm cov neeg ua haujlwm muaj peev xwm kawm hauv SIS xeem, cov txheej txheem pov thawj, thiab SIS loops lawv yuav raug sim. Yuav tsum muaj kev taug kev ntawm cov txheej txheem ua ntej ua qhov kev sim ua pov thawj thawj zaug, thiab tawm tswv yim rau lub vev xaib SIS Technical Authority tom qab ntawd txhawm rau txhim kho lossis kho.
Muaj ob hom kev ua tsis tiav (kev nyab xeeb lossis txaus ntshai), uas tau muab faib ua plaub hom - tsis pom kev txaus ntshai, kuaj pom tsis zoo (los ntawm kev kuaj mob), tsis pom zoo thiab kuaj pom muaj kev nyab xeeb. Cov ntsiab lus txaus ntshai thiab txaus ntshai uas tsis pom zoo tsis ua haujlwm yog siv sib pauv hauv kab lus no.
Hauv SIF cov ntaub ntawv pov thawj, peb feem ntau txaus siab rau cov hom kev phom sij uas tsis tuaj yeem kuaj pom, tab sis yog tias muaj cov neeg siv tshuaj ntsuam xyuas pom qhov ua tsis tiav txaus ntshai, cov kev kuaj mob no yuav tsum tau kuaj pov thawj. Nco ntsoov tias tsis zoo li cov neeg siv tshuaj ntsuam xyuas, cov cuab yeej hauv kev kuaj mob feem ntau tsis tuaj yeem siv tau raws li kev ua haujlwm los ntawm tus neeg siv, thiab qhov no tuaj yeem cuam tshuam cov pov thawj kev sim siab. Thaum cov qhab nia rau kev kuaj mob raug coj mus rau hauv SIL suav, cov tshuaj ntsuam xyuas lub tswb (xws li lub tswb tsis muaj ntau) yuav tsum tau sim ua ib feem ntawm cov ntawv pov thawj.
Cov hom kev ua tsis tiav tuaj yeem muab faib ntxiv rau cov kev sim rau thaum lub sijhawm ua pov thawj, cov uas tsis tau sim rau, thiab kev ua tsis tiav los yog lub sijhawm ua tsis tiav. Qee yam kev ua tsis tau zoo yuav tsis raug kuaj ncaj qha rau ntau yam laj thawj (xws li nyuaj, engineering lossis kev txiav txim siab ua haujlwm, tsis paub, tsis muaj peev xwm, omission lossis commission tsis raug cai, tsis tshua muaj tshwm sim, thiab lwm yam). Yog tias muaj cov kev paub ua tsis tiav uas yuav tsis raug kuaj rau, kev them nyiaj yuav tsum tau ua hauv kev tsim cov cuab yeej, cov txheej txheem kuaj, hloov khoom siv ib ntus lossis rov tsim kho dua, thiab / lossis kev ntsuas tsis txaus ntseeg yuav tsum tau ua kom txo qis qhov cuam tshuam ntawm SIF kev ncaj ncees ntawm kev tsis kuaj.
Ib qho kev ua tsis tiav yog ib lub xeev uas tsis zoo los yog qhov xwm txheej xws li qhov tseem ceeb, tsis txaus ntseeg tuaj yeem xav tias yuav tshwm sim yog tias tsis tau kho kom raug raws sijhawm. Lawv feem ntau raug kuaj pom los ntawm kev ua tau zoo sib piv rau cov ntawv pov thawj tsis ntev los no lossis thawj qhov kev ntsuas pov thawj (xws li kos npe valve lossis lub sijhawm teb lub valve) lossis los ntawm kev tshuaj xyuas (xws li cov txheej txheem ntsaws). Kev ua tsis tiav feem ntau yog nyob ntawm lub sijhawm-lub sijhawm ntev ntawm lub cuab yeej lossis kev sib dhos ua haujlwm, qhov ntau degraded nws dhau los; Cov xwm txheej uas pab txhawb qhov tsis ua haujlwm tsis zoo yuav ua rau muaj kev cuam tshuam ntau dua, cov txheej txheem chaw nres nkoj ntsaws lossis lub ntsuas hluav taws xob ntau dhau sijhawm, lub neej muaj txiaj ntsig tau khiav tawm, thiab lwm yam. Yog li ntawd, qhov ntev ntawm cov ntawv pov thawj lub sijhawm, qhov feem ntau yuav tshwm sim lossis tsis ua haujlwm raws sijhawm. Txhua qhov kev tiv thaiv tiv thaiv qhov ua tsis tiav kuj yuav tsum tau kuaj pov thawj (chaw nres nkoj purging, ntsuas kub, thiab lwm yam).
Cov txheej txheem yuav tsum tau sau rau cov ntawv pov thawj rau qhov txaus ntshai (tsis pom zoo) ua tsis tiav. Hom kev ua tsis tiav thiab kev tsom xam cov txiaj ntsig (FMEA) lossis hom tsis ua haujlwm, cov txiaj ntsig thiab kev tshuaj ntsuam xyuas (FMEDA) cov txheej txheem tuaj yeem pab txheeb xyuas qhov ua tsis tau zoo uas tsis pom zoo, thiab qhov kev pov thawj kuaj yuav tsum tau txhim kho.
Ntau cov txheej txheem kuaj pov thawj yog sau raws li kev paub dhau los thiab cov qauv los ntawm cov txheej txheem uas twb muaj lawm. Cov txheej txheem tshiab thiab nyuaj SIFs hu rau kev tsim kho dua tshiab uas siv FMEA / FMEDA los tshuaj xyuas qhov ua tsis tiav txaus ntshai, txiav txim siab seb cov txheej txheem xeem yuav ua li cas lossis yuav tsis kuaj rau cov kev ua tsis tiav, thiab kev them nqi ntawm cov kev xeem. Lub macro-theem tsis ua hauj lwm hom kev tsom xam thaiv daim duab rau ib lub sensor yog pom nyob rau hauv daim duab 2. FMEA feem ntau tsuas yog yuav tsum tau ua ib zaug rau ib hom khoom siv thiab rov siv dua rau cov cuab yeej zoo sib xws nrog kev txiav txim siab ntawm lawv cov txheej txheem kev pabcuam, kev teeb tsa thiab qhov chaw kuaj muaj peev xwm. .
Macro-theem tsis ua hauj lwm tsom xam Daim duab 2: Qhov no macro-theem tsis ua hauj lwm hom kev tsom xam thaiv daim duab rau lub sensor thiab siab transmitter (PT) qhia txog lub luag haujlwm tseem ceeb uas feem ntau yuav raug rhuav tshem mus rau ntau qhov kev ntsuam xyuas micro tsis ua hauj lwm txhawm rau txheeb xyuas qhov ua tsis tau tiav. hauv cov kev xeem ua haujlwm.
Daim duab 2: Qhov no macro-theem tsis ua hauj lwm hom kev tsom xam thaiv daim duab rau lub sensor thiab siab transmitter (PT) qhia tau hais tias lub luag haujlwm tseem ceeb uas feem ntau yuav raug rhuav tshem mus rau ntau qhov kev ntsuam xyuas micro tsis ua hauj lwm kom tag nrho txhais cov kev ua tsis tiav uas yuav tsum tau hais nyob rau hauv qhov kev xeem ua haujlwm.
Qhov feem pua ntawm qhov paub, txaus ntshai, tsis pom zoo ua pov thawj tau kuaj yog hu ua pov thawj kev pov hwm kev pov hwm (PTC). PTC feem ntau yog siv rau hauv SIL xam los "paub" rau qhov tsis ua tiav kev sim ntau dua SIF. Cov neeg muaj kev ntseeg yuam kev vim tias lawv tau txiav txim siab tias tsis muaj kev sim ntsuas hauv lawv qhov kev suav SIL, lawv tau tsim SIF txhim khu kev qha. Qhov tseeb yooj yim yog, yog tias koj qhov kev ntsuam xyuas kev pov hwm yog 75%, thiab yog tias koj ntsuas tus lej ntawd rau hauv koj qhov kev suav SIL thiab kuaj cov khoom koj twb tau sim ntau zaus, 25% ntawm qhov tsis txaus ntseeg tseem tuaj yeem tshwm sim. Kuv paub tseeb tias tsis xav nyob hauv 25%.
FMEDA cov ntawv ceeb toom pom zoo thiab phau ntawv qhia kev nyab xeeb rau cov khoom siv feem ntau muab cov txheej txheem pov thawj yam tsawg kawg nkaus thiab kev pov thawj pov thawj. Cov no tsuas yog muab kev taw qhia xwb, tsis yog tag nrho cov kauj ruam xeem uas yuav tsum tau ua rau cov txheej txheem ua pov thawj tiav. Lwm hom kev ntsuam xyuas tsis ua hauj lwm, xws li kev tsom xam cov ntoo txhaum thiab kev ntseeg siab ntawm kev saib xyuas, kuj tseem siv los txheeb xyuas qhov ua tsis tiav txaus ntshai.
Cov ntaub ntawv pov thawj tuaj yeem muab faib ua haujlwm tag nrho (kawg-rau-kawg) lossis kev sim ua haujlwm ib nrab (Daim duab 3). Kev sim ua haujlwm ib nrab feem ntau ua tiav thaum cov khoom ntawm SIF muaj qhov sib txawv ntawm qhov kev xeem sib txawv hauv SIL xam uas tsis ua raws li kev npaj kaw lossis hloov pauv. Nws yog ib qho tseem ceeb uas cov txheej txheem ua pov thawj ua haujlwm ib nrab sib tshooj xws li ua ke lawv sim txhua qhov kev nyab xeeb ntawm SIF. Nrog rau kev sim ua haujlwm ib nrab, nws tseem pom zoo tias SIF muaj qhov pib qhov kawg-rau-kawg pov thawj, thiab cov tom ntej thaum hloov pauv.
Cov ntawv pov thawj ib nrab yuav tsum tau ntxiv rau daim duab 3: Cov kev xeem ua pov thawj ua ke (hauv qab) yuav tsum npog tag nrho cov haujlwm ntawm kev ua haujlwm pov thawj tag nrho (sab saum toj).
Daim duab 3: Cov kev xeem ua pov thawj ua ke (hauv qab) yuav tsum npog tag nrho cov kev ua haujlwm ntawm cov ntawv pov thawj tag nrho (sab saum toj).
Ib qho pov thawj ib nrab tsuas yog ntsuas qhov feem pua ntawm cov khoom siv tsis ua haujlwm. Ib qho piv txwv feem ntau yog kev kuaj ib nrab-stroke valve, qhov twg lub valve tau txav me me (10-20%) kom paub tseeb tias nws tsis daig. Qhov no muaj qhov pov thawj qis dua qhov kev xeem pov thawj ntawm qhov kev xeem thawj zaug.
Cov txheej txheem kuaj pov thawj tuaj yeem sib txawv hauv qhov nyuaj nrog qhov nyuaj ntawm SIF thiab lub tuam txhab kev sim txheej txheem kev xav. Qee lub tuam txhab sau cov txheej txheem sim ua ib kauj ruam, thaum lwm tus muaj cov txheej txheem luv luv. Kev xa mus rau lwm cov txheej txheem, xws li kev ntsuas tus qauv, qee zaum siv los txo qhov loj ntawm cov txheej txheem kuaj pov thawj thiab pab kom muaj kev sib luag hauv kev sim. Cov txheej txheem pov thawj zoo yuav tsum muab cov ncauj lus kom ntxaws kom paub meej tias txhua qhov kev sim ua tiav thiab sau tseg, tab sis tsis muaj ntau yam nthuav dav ua rau cov kws tshaj lij xav hla cov kauj ruam. Muaj tus kws tshaj lij, uas yog lub luag haujlwm rau kev ua cov kauj ruam xeem, thawj kauj ruam ua tiav tuaj yeem pab xyuas kom meej tias qhov kev xeem yuav ua tiav. Kev kos npe tawm ntawm cov ntawv pov thawj ua tiav los ntawm Instrument Supervisor thiab cov neeg sawv cev ua haujlwm tseem yuav hais txog qhov tseem ceeb thiab paub tseeb tias qhov kev xeem ua pov thawj tiav.
Cov tswv yim kws kho mob yuav tsum tau caw kom pab txhim kho cov txheej txheem. Kev ua tiav ntawm cov txheej txheem kuaj pov thawj yog nyob rau hauv feem ntau ntawm cov kws tshaj lij txhais tes, yog li kev sib koom tes tau pom zoo.
Feem ntau qhov kev ntsuam xyuas pov thawj feem ntau yog ua tiav off-line thaum lub sijhawm kaw lossis hloov pauv. Qee zaum, kev xeem ntawv pov thawj yuav tsum tau ua hauv online thaum khiav kom txaus siab rau SIL suav lossis lwm yam yuav tsum tau ua. Kev sim online xav tau kev npaj thiab kev sib koom tes nrog Kev Ua Haujlwm kom tso cai rau kev sim ua pov thawj kom muaj kev nyab xeeb, tsis muaj txheej txheem ntxhov siab, thiab tsis ua rau muaj kev mus ncig tsis zoo. Nws tsuas yog siv ib qho kev mus txawv tebchaws los siv tag nrho koj cov attaboys. Thaum lub sij hawm qhov kev xeem no, thaum SIF tsis muaj tag nrho los ua nws txoj hauj lwm kev nyab xeeb, 61511-1, Clause 11.8.5, hais tias "Kev them nuj nqis uas ua kom muaj kev ruaj ntseg txuas ntxiv yuav tsum tau muab raws li 11.3 thaum SIS nyob hauv. bypass (kho lossis kuaj). Cov txheej txheem tswj qhov xwm txheej txawv txav yuav tsum mus nrog cov txheej txheem kuaj pov thawj los pab kom paub tseeb tias qhov no ua tiav.
SIF feem ntau muab faib ua peb qhov tseem ceeb: sensors, logic solvers thiab cov ntsiab lus kawg. Kuj tseem muaj cov cuab yeej pabcuam uas tuaj yeem koom nrog hauv txhua qhov ntawm peb qhov no (xws li IS teeb meem, kev mus ncig amps, interposing relays, solenoids, thiab lwm yam) uas yuav tsum tau sim. Cov ntsiab lus tseem ceeb ntawm kev ntsuas pov thawj txhua yam ntawm cov thev naus laus zis no tuaj yeem pom nyob rau hauv sidebar, "Tsim sensors, logic solvers thiab cov ntsiab lus kawg" (hauv qab).
Qee yam yooj yim dua rau kev sim ua pov thawj dua li lwm tus. Ntau cov niaj hnub thiab ob peb lub qub ntws thiab qib technologies yog nyob rau hauv qeb nyuaj dua. Cov no suav nrog Coriolis flowmeters, vortex meters, mag meters, los ntawm huab cua radar, qib ultrasonic, thiab cov txheej txheem hauv-situ, rau npe rau ob peb tug. Hmoov zoo, tam sim no ntau ntawm cov no tau txhim kho kev kuaj mob uas tso cai rau kev txhim kho kev sim.
Qhov nyuaj ntawm cov pov thawj kuaj xws li cov cuab yeej hauv thaj chaw yuav tsum tau txiav txim siab hauv SIF tsim. Nws yog ib qho yooj yim rau engineering xaiv SIF cov cuab yeej yam tsis muaj kev txiav txim siab loj ntawm qhov yuav tsum tau ua pov thawj rau cov cuab yeej siv, vim lawv yuav tsis yog cov neeg sim lawv. Qhov no kuj yog qhov tseeb ntawm kev kuaj ib nrab-stroke, uas yog ib txoj hauv kev los txhim kho SIF qhov nruab nrab qhov ua tsis tau raws li qhov xav tau (PFDavg), tab sis tom qab cog kev ua haujlwm tsis xav ua, thiab ntau zaus yuav tsis ua. Ib txwm muab kev saib xyuas cov nroj tsuag ntawm kev tsim vaj tsev ntawm SIFs hais txog kev ntsuas pov thawj.
Cov ntaub ntawv pov thawj yuav tsum suav nrog kev tshuaj xyuas ntawm SIF kev teeb tsa thiab kho raws li xav tau kom ua tau raws li 61511-1, Tshooj 16.3.2. Yuav tsum muaj kev tshuaj ntsuam xyuas zaum kawg kom paub tseeb tias txhua yam yog khawm, thiab ob npaug xyuas tias SIF tau muab tso rau hauv cov txheej txheem ua haujlwm zoo.
Kev sau ntawv thiab siv cov txheej txheem xeem zoo yog ib kauj ruam tseem ceeb los xyuas kom meej qhov kev ncaj ncees ntawm SIF dhau nws lub neej. Cov txheej txheem xeem yuav tsum muab cov ntsiab lus txaus los xyuas kom meej tias cov kev xeem yuav tsum tau ua tas li thiab muaj kev nyab xeeb thiab ua tiav. Kev phom sij tsis zoo uas tsis raug kuaj los ntawm cov ntawv pov thawj yuav tsum tau them rov qab los xyuas kom meej tias SIF txoj kev ruaj ntseg ruaj ntseg txaus nyob rau hauv nws lub neej.
Kev sau cov txheej txheem pov thawj zoo yuav tsum muaj txoj hauv kev rau kev tshawb xyuas engineering ntawm qhov muaj peev xwm txaus ntshai tsis ua haujlwm, xaiv cov txhais tau tias, thiab sau cov ntawv pov thawj cov kauj ruam uas nyob rau hauv cov nroj tsuag kev sim muaj peev xwm. Nyob rau hauv txoj kev, tau cog yuav-hauv txhua qib rau kev sim, thiab cob qhia cov kws tshaj lij los ua thiab sau cov ntawv pov thawj thiab nkag siab qhov tseem ceeb ntawm qhov kev xeem. Sau cov lus qhia zoo li yog tias koj yog tus kws tshaj lij cov cuab yeej uas yuav tau ua haujlwm, thiab lub neej ntawd nyob ntawm qhov tau txais qhov kev xeem, vim lawv ua.
Testing sensors, logic solvers and final elements A SIF is typically divided up into three main parts, sensors, logic solvers and final elements. There also typically are auxiliary devices that can be associated within each of these three parts (e.g. I.S. barriers, trip amps, interposing relays, solenoids, etc.) that must also be tested.Sensor proof tests: The sensor proof test must ensure that the sensor can sense the process variable over its full range and transmit the proper signal to the SIS logic solver for evaluation. While not inclusive, some of the things to consider in creating the sensor portion of the proof test procedure are given in Table 1. Table 1: Sensor proof test considerations Process ports clean/process interface check, significant buildup noted Internal diagnostics check, run extended diagnostics if available Sensor calibration (5 point) with simulated process input to sensor, verified through to the DCS, drift check Trip point check High/High-High/Low/Low-Low alarms Redundancy, voting degradation Out of range, deviation, diagnostic alarms Bypass and alarms, restrike User diagnostics Transmitter Fail Safe configuration verified Test associated systems (e.g. purge, heat tracing, etc.) and auxiliary components Physical inspection Complete as-found and as-left documentation Logic solver proof test: When full-function proof testing is done, the logic solver’s part in accomplishing the SIF’s safety action and related actions (e.g. alarms, reset, bypasses, user diagnostics, redundancies, HMI, etc.) are tested. Partial or piecemeal function proof tests must accomplish all these tests as part of the individual overlapping proof tests. The logic solver manufacturer should have a recommended proof test procedure in the device safety manual. If not and as a minimum, the logic solver power should be cycled, and the logic solver diagnostic registers, status lights, power supply voltages, communication links and redundancy should be checked. These checks should be done prior to the full-function proof test.Don’t make the assumption that the software is good forever and the logic need not be tested after the initial proof test as undocumented, unauthorized and untested software and hardware changes and software updates can creep into systems over time and must be factored into your overall proof test philosophy. The management of change, maintenance, and revision logs should be reviewed to ensure they are up to date and properly maintained, and if capable, the application program should be compared to the latest backup.Care should also be taken to test all the user logic solver auxiliary and diagnostic functions (e.g. watchdogs, communication links, cybersecurity appliances, etc.).Final element proof test: Most final elements are valves, however, rotating equipment motor starters, variable-speed drives and other electrical components such as contactors and circuit breakers are also used as final elements and their failure modes must be analyzed and proof tested.The primary failure modes for valves are being stuck, response time too slow or too fast, and leakage, all of which are affected by the valve’s operating process interface at trip time. While testing the valve at operating conditions is the most desirable case, Operations would generally be opposed to tripping the SIF while the plant is operating. Most SIS valves are typically tested while the plant is down at zero differential pressure, which is the least demanding of operating conditions. The user should be aware of the worst-case operational differential pressure and the valve and process degradation effects, which should be factored into the valve and actuator design and sizing.Commonly, to compensate for not testing at process operating conditions, additional safety pressure/thrust/torque margin is added to the valve actuator and inferential performance testing is done utilizing baseline testing. Examples of these inferential tests are where the valve response time is timed, a smart positioner or digital valve controller is used to record a valve pressure/position curve or signature, or advance diagnostics are done during the proof test and compared with previous test results or baselines to detect valve performance degradation, indicating a potential incipient failure. Also, if tight shut off (TSO) is a requirement, simply stroking the valve will not test for leakage and a periodic valve leak test will have to be performed. ISA TR96.05.02 is intended to provide guidance on four different levels of testing of SIS valves and their typical proof test coverage, based on how the test is instrumented. People (particularly users) are encouraged to participate in the development of this technical report (contact crobinson@isa.org).Ambient temperatures can also affect valve friction loads, so that testing valves in warm weather will generally be the least demanding friction load when compared to cold weather operation. As a result, proof testing of valves at a consistent temperature should be considered to provide consistent data for inferential testing for the determination of valve performance degradation.Valves with smart positioners or a digital valve controller generally have capability to create a valve signature that can be used to monitor degradation in valve performance. A baseline valve signature can be requested as part of your purchase order or you can create one during the initial proof test to serve as a baseline. The valve signature should be done for both opening and closing of the valve. Advanced valve diagnostic should also be used if available. This can help tell you if your valve performance is deteriorating by comparing subsequent proof test valve signatures and diagnostics with your baseline. This type of test can help compensate for not testing the valve at worst case operating pressures.The valve signature during a proof test may also be able to record the response time with time stamps, removing the need for a stopwatch. Increased response time is a sign of valve deterioration and increased friction load to move the valve. While there are no standards regarding changes in valve response time, a negative pattern of changes from proof test to proof test is indicative of the potential loss of the valve’s safety margin and performance. Modern SIS valve proof testing should include a valve signature as a matter of good engineering practice.The valve instrument air supply pressure should be measured during a proof test. While the valve spring for a spring-return valve is what closes the valve, the force or torque involved is determined by how much the valve spring is compressed by the valve supply pressure (per Hooke’s Law, F = kX). If your supply pressure is low, the spring will not compress as much, hence less force will be available to move the valve when needed. While not inclusive, some of the things to consider in creating the valve portion of the proof test procedure are given in Table 2. Table 2: Final element valve assembly considerations Test valve safety action at process operating pressure (best but typically not done), and time the valve’s response time. Verify redundancy Test valve safety action at zero differential pressure and time valve’s response time. Verify redundancy Run valve signature and diagnostics as part of proof test and compare to baseline and previous test Visually observe valve action (proper action without unusual vibration or noise, etc.). Verify the valve field and position indication on the DCS Fully stroke the valve a minimum of five times during the proof test to help ensure valve reliability. (This is not intended to fix significant degradation effects or incipient failures). Review valve maintenance records to ensure any changes meet the required valve SRS specifications Test diagnostics for energize-to-trip systems Leak test if Tight Shut Off (TSO) is required Verify the command disagree alarm functionality Inspect valve assembly and internals Remove, test and rebuild as necessary Complete as-found and as-left documentation Solenoids Evaluate venting to provide required response time Evaluate solenoid performance by a digital valve controller or smart positioner Verify redundant solenoid performance (e.g. 1oo2, 2oo3) Interposing Relays Verify correct operation, redundancy Device inspection
Ib qho SIF feem ntau muab faib ua peb qhov tseem ceeb, sensors, logic solvers thiab cov ntsiab lus kawg. Kuj tseem muaj cov cuab yeej pab cuam uas tuaj yeem cuam tshuam hauv txhua qhov ntawm peb qhov no (xws li IS cov teeb meem, kev mus ncig amps, interposing relays, solenoids, thiab lwm yam) uas yuav tsum tau sim.
Cov ntawv pov thawj Sensor: Cov ntawv pov thawj sensor yuav tsum xyuas kom meej tias lub sensor tuaj yeem nkag siab cov txheej txheem sib txawv ntawm nws qhov ntau thiab xa cov teeb liab tsim nyog rau SIS logic solver rau kev ntsuam xyuas. Txawm hais tias tsis suav nrog, qee yam uas yuav tsum tau xav txog hauv kev tsim cov sensor ib feem ntawm cov txheej txheem kuaj pov thawj tau muab rau hauv Table 1.
Logic solver proof test: Thaum cov ntaub ntawv pov thawj tiav tiav lawm, cov logic solver yog ib feem ntawm kev ua tiav SIF txoj kev nyab xeeb thiab lwm yam kev ua (xws li lub tswb, pib dua, bypasses, neeg siv tshuaj ntsuam xyuas, redundancies, HMI, thiab lwm yam) raug kuaj. Ib feem lossis cov ntawv pov thawj ua haujlwm ib nrab yuav tsum ua kom tiav tag nrho cov kev xeem no ua ib feem ntawm tus neeg sib tshooj pov thawj. Cov chaw tsim khoom logic solver yuav tsum muaj cov txheej txheem pov thawj pom zoo hauv phau ntawv qhia kev nyab xeeb ntawm cov cuab yeej. Yog tias tsis yog thiab qhov tsawg kawg nkaus, lub logic solver fais fab yuav tsum tau cycled, thiab cov logic solver diagnostic registers, xwm txheej teeb, fais fab mov voltages, kev sib txuas lus thiab redundancy yuav tsum tau kuaj xyuas. Cov kev kuaj xyuas no yuav tsum tau ua ua ntej qhov kev xeem ua pov thawj tiav.
Tsis txhob ua qhov kev xav tias software zoo mus ib txhis thiab cov logic yuav tsum tsis txhob sim tom qab thawj qhov kev xeem pov thawj raws li cov ntaub ntawv tsis muaj ntaub ntawv, tsis muaj kev tso cai thiab tsis tau kuaj xyuas software thiab kho vajtse hloov pauv thiab software hloov tshiab tuaj yeem nkag mus rau hauv lub sijhawm dhau los thiab yuav tsum tau muab tso rau hauv koj tag nrho. pov thawj test philosophy. Kev tswj hwm ntawm kev hloov pauv, kev saib xyuas, thiab kev hloov kho cav yuav tsum tau tshuaj xyuas kom paub tseeb tias lawv hloov kho thiab khaws cia kom raug, thiab yog tias muaj peev xwm, cov ntawv thov kev pab cuam yuav tsum muab piv rau cov thaub qab tshiab kawg.
Kev saib xyuas kuj tseem yuav tsum tau coj mus kuaj tag nrho cov neeg siv cov logic solver pabcuam thiab kuaj cov haujlwm (xws li cov neeg saib xyuas, kev sib txuas lus, cov khoom siv cybersecurity, thiab lwm yam).
Cov khoom pov thawj zaum kawg: Feem ntau cov ntsiab lus kawg yog li qub, txawm li cas los xij, cov khoom siv lub cev muaj zog tig, hloov pauv-ceev tsav thiab lwm yam khoom siv hluav taws xob xws li contactors thiab Circuit Court breakers kuj tseem siv los ua cov ntsiab lus kawg thiab lawv cov qauv tsis ua haujlwm yuav tsum tau soj ntsuam thiab kuaj pov thawj.
Cov hom tsis ua haujlwm tseem ceeb rau cov li qub tau raug daig, lub sij hawm teb qeeb dhau los yog nrawm dhau, thiab cov dej xau, tag nrho cov cuam tshuam los ntawm lub valve kev khiav hauj lwm txheej txheem interface ntawm lub sij hawm mus txawv tebchaws. Thaum kuaj lub valve ntawm kev ua haujlwm yog qhov xav tau tshaj plaws, Kev Ua Haujlwm feem ntau yuav tawm tsam rau kev poob ntawm SIF thaum cov nroj tsuag ua haujlwm. Feem ntau SIS li qub feem ntau raug sim thaum cov nroj tsuag poob ntawm xoom qhov sib txawv siab, uas yog qhov xav tau tsawg tshaj plaws ntawm kev ua haujlwm. Tus neeg siv yuav tsum paub txog qhov ua haujlwm tsis zoo ntawm qhov sib txawv siab thiab lub valve thiab cov txheej txheem degradation cuam tshuam, uas yuav tsum tau muab tso rau hauv lub valve thiab actuator tsim thiab sizing.
Commonly, to compensate for not testing at process operating conditions, additional safety pressure/thrust/torque margin is added to the valve actuator and inferential performance testing is done utilizing baseline testing. Examples of these inferential tests are where the valve response time is timed, a smart positioner or digital valve controller is used to record a valve pressure/position curve or signature, or advance diagnostics are done during the proof test and compared with previous test results or baselines to detect valve performance degradation, indicating a potential incipient failure. Also, if tight shut off (TSO) is a requirement, simply stroking the valve will not test for leakage and a periodic valve leak test will have to be performed. ISA TR96.05.02 is intended to provide guidance on four different levels of testing of SIS valves and their typical proof test coverage, based on how the test is instrumented. People (particularly users) are encouraged to participate in the development of this technical report (contact crobinson@isa.org).
Qhov kub thiab txias kuj tseem tuaj yeem cuam tshuam qhov kev sib txhuam ntawm lub valve, yog li kev ntsuas qhov ntsuas hauv huab cua sov feem ntau yog qhov xav tau kev sib txhuam tsawg tshaj plaws thaum piv rau huab cua txias. Yog li ntawd, kev ntsuas pov thawj ntawm cov li qub ntawm qhov kub thiab txias yuav tsum tau txiav txim siab los muab cov ntaub ntawv zoo ib yam rau kev ntsuas kev ntsuas rau kev txiav txim siab ntawm kev ua haujlwm ntawm lub valve.
Valves nrog smart positioners los yog digital valve controller feem ntau muaj peev xwm los tsim ib lub npe kos npe uas tuaj yeem siv los saib xyuas kev ua haujlwm ntawm lub valve. Daim ntawv kos npe lub hauv paus tuaj yeem thov los ua ib feem ntawm koj daim ntawv xaj khoom lossis koj tuaj yeem tsim ib qho thaum lub sij hawm ua pov thawj thawj zaug los ua lub hauv paus. Lub valve kos npe yuav tsum tau ua rau ob qho tib si qhib thiab kaw ntawm lub valve. Advanced valve diagnostic yuav tsum tau siv yog tias muaj. Qhov no tuaj yeem pab qhia koj yog tias koj qhov kev ua tau zoo ntawm lub valve tsis zoo los ntawm kev sib piv cov ntaub ntawv pov thawj tom ntej ntawm lub valve kos npe thiab kev kuaj mob nrog koj lub hauv paus. Hom kev sim no tuaj yeem pab them nyiaj rau qhov tsis kuaj lub valve ntawm qhov phem tshaj plaws kev khiav hauj lwm siab.
Lub valve kos npe thaum lub sij hawm ua pov thawj kuj tseem tuaj yeem sau cov lus teb nrog lub sij hawm thwj, tshem tawm qhov xav tau rau lub sijhawm nres. Lub sij hawm teb nce ntxiv yog ib qho kev qhia ntawm valve deterioration thiab nce kev sib txhuam kom txav lub valve. Txawm hais tias tsis muaj cov qauv hais txog kev hloov pauv hauv lub sijhawm teb lub valve, tus qauv tsis zoo ntawm cov kev hloov pauv los ntawm cov ntawv pov thawj rau kev kuaj pov thawj yog qhov qhia tau tias muaj peev xwm poob ntawm lub valve txoj kev nyab xeeb thiab kev ua haujlwm. Niaj hnub nimno SIS valve pov thawj yuav tsum muaj xws li ib tug kos npe valve raws li ib tug teeb meem ntawm zoo engineering xyaum.
Lub valve ntsuas cua qhov siab yuav tsum tau ntsuas thaum lub sij hawm ua pov thawj. Thaum lub caij nplooj ntoos hlav lub caij nplooj ntoos hlav rau lub caij nplooj ntoos hlav rov qab yog dab tsi kaw lub valve, lub zog lossis lub zog cuam tshuam yog txiav txim siab los ntawm ntau npaum li cas lub valve lub caij nplooj ntoos hlav compressed los ntawm lub valve muab siab (raws li Hooke Txoj Cai, F = kX). Yog tias koj cov khoom siv siab tsawg, lub caij nplooj ntoos hlav yuav tsis compress ntau npaum li cas, yog li lub zog tsawg yuav muaj los txav lub valve thaum xav tau. Thaum tsis suav nrog, qee yam uas yuav tsum tau xav txog hauv kev tsim lub valve ntawm cov txheej txheem kuaj pov thawj tau muab rau hauv Table 2.
Post lub sij hawm: Nov-13-2019
