Menene kyawawan hanyoyin aiwatarwa don sa ido kan vibreshin na 3500/42 a cikin tsarukan PLC?

Haɗa Bently Nevada 3500/42 da PLCs: Bincike na Fasaha Mai zurfi ga Injiniyoyi

Gazawar injinan juyawa suna daga cikin abubuwan da suka fi tsada a ayyukan masana’antu. Fashewa ko tsayawar turbin guda ɗaya ko na’urar matsa iska na iya haifar da asara da ta wuce dala miliyan $2 a kowane awa a manyan cibiyoyi. Duk da yake Bently Nevada 3500/42 tana bayar da matuƙar daidaiton auna girgiza, ainihin ƙimar ta tana bayyana ne kawai idan an haɗa ta kai tsaye cikin tsarin sarrafa PLC ko DCS. Wannan maqala tana ba da jagorar matakin injiniya kan yadda za a cimma haɗin kai mai dogaro, mai ƙarancin jinkiri wanda ke sauya tsuntsen bayanan girgiza na asali zuwa kariyar inji ta atomatik.

Fahimtar Silsilar Siginar Fitarwa ta 3500/42

Na’urar 3500/42 tana sarrafa shigar daga na’urorin auna kusanci (proximity probes) ko accelerometers kuma tana haifar da nau’o’in fitarwa da dama. Waɗannan sun haɗa da siginar wuta ko ƙarfi (current) masu daidaito da girman siginar (yawanci 4-20 mA), buffered transducer outputs, da na’urorin ƙararrawa na dijital (digital alarm relays). Don haɗawa da PLC, da’irar analog 4-20 mA ita ce mafi sauƙin hanya. Kowace ƙarin miliamp tana daidaita da wani takamaiman ƙarar girgiza, wanda ke ba da damar katin shigar analog na PLC ya ma’auna ƙimar kai tsaye zuwa raka’o’in injiniya kamar mm/s ko mils.

Zaɓar Tsarin Shigar PLC da Ya Fi Dacewa

PLCs na zamani suna bayar da manyan zaɓuɓɓuka biyu don kama bayanan girgiza. Katin shigar analog masu ƙudurin 16-bit suna ba da daidaito mai kyau don sa ido kan canje-canje da faɗakarwa. Sai dai, ga injinan da suke da matuƙar muhimmanci inda nazarin mataki (phase) da mitoci (frequency) ke da muhimmanci, a yi la’akari da amfani da na’urorin ƙididdiga masu sauri (high-speed counter modules) ko katin shigar girgiza na musamman da ke yin samfurori a saurin sama da 20 kHz. 3500/42 na iya fitar da siginar sigogi (dynamic signals) na asali ta hanyar buffered outputs ɗinsa. Haɗa waɗannan zuwa shigar PLC masu sauri yana ba da damar kama siffar igiyar lokaci (time-domain waveform) da yin asalin nazarin FFT kai tsaye a cikin mahallin tsarin sarrafa na’ura.

Kyawawan Hanyoyin Gyaran Sigina da Ware Lantarki (Electrical Isolation)

Muhallin masana’antu yana ɗauke da hanyoyi da dama na hayaniya: injin sarrafa saurin mota (variable frequency drives), kunna lambobin tuntuɓa (contactor switching), da kuma watsawar rediyo. Hayaniya marar so da ta haɗu cikin siginar girgiza na iya jawo ƙararrawa na ƙarya ko ɓacewar gano matsala. Injiniyoyi dole ne su aiwatar da ingantattun dabarun gyaran sigina (signal conditioning).

Tsarin Haɗin Ƙasa (Grounding Topology) don Auna Sigina Masu Ƙananan Hayaniya

Haɗa ƙasa a wuri guda (single-point grounding) har yanzu shi ne ma'aunin zinare. Haɗa ƙasan na'urar 3500/42 kai tsaye da sandar bus bar na ƙasan kayan a shukar. Ka guji ɗaure ƙasa ta hanyar jere (daisy-chaining) daga na'ura zuwa wata. Module na shigar analog na PLC ya kamata ya yi nuni zuwa wannan matakin ƙasa ɗaya. Idan tazarar tsakanin 3500/42 da PLC ta haura mita 30, yi amfani da na'urorin da ke ware sigina (isolated signal conditioners) don karya ground loops. Waɗannan na'urori kuma suna ba da kariyar tasirin tashin wuta, suna kare duka tsarin daga wuce-gonar wuta na ɗan lokaci.

Ka'idojin Zaɓen Igiyoyi da Hanyar Janyarsu

Yi amfani da igiyoyi twisted-pair masu kariya guda-guda (individually shielded) ga kowace siginar jijjiga. Belden 8761 ko makamancinsa yana ba da kyakkyawan kariya daga hayaniya. Ka kiyaye aƙalla tazarar santimita 30 tsakaninsu da igiyoyin wutar lantarki da layukan fitar VFD. Idan ba za a iya guje wa ketare igiyoyin wuta ba, sai a ketare su a kusurwar digiri 90 don rage inductive coupling. A gama kariyar (shield) ne kawai a gefen PLC sai dai idan littafin umarnin 3500/42 ya fayyace wani abu daban. Barin kariyar a buɗe a gefen firikwensin yana hana zagayawar kwarara ta ƙasa.

Saita Iyakokin Ƙararrawa Bisa Nau'in Injin

Saita matakan ƙararrawa da matakan kashewa yadda ya dace na buƙatar fahimtar duka ƙa'idodin ISO da kuma siffofin musamman na kayan aikin. Teburin da ke ƙasa yana ba da shawarwarin matakan farawa da aka samo daga yadda ake aiwatarwa a masana'antu.

Daidaice Iyakokin Ƙararrawa Ga Injinan da Saurinsu Ke Canzawa

Matakan ƙararrawa na dindindin ba sa aiki da kyau a kan kayan aiki da ke aiki a manyan bambance-bambancen sauri. Dole a daidaita iyakokin jijjiga da saurin juyawa. Shirya PLC ɗinka ya karanta ainihin saurin injin daga tachometer ko encoder. Sannan ka ƙididdige matakan ƙararrawa ta amfani da dabara: Alert = Baseline + (Speed_ratio × 2 mm/s). Wannan dabara tana hana katsewa marasa amfani a ƙananan sauri yayin da take kiyaye ƙarfafawa a manyan sauri. Aiwhwatar da lojin a cikin function block da ke gudana kowane milisekan 100 domin kariya mai saurin amsawa.

Lojin Shirin PLC don Kullewa Bisa Jijjiga

Injiniyoyi dole su ƙera ladder logic ko structured text da ke ba da fifiko ga tsaro da ci gaba da aiki a lokaci guda. Pseudocode da ke ƙasa yana nuna tsarin aiwatarwa mai ƙarfi.

Nazarin Lamurra na Fasaha na Duniya ta Gaskiya tare da Cikakkun Ma'aunai

Nazarin Lamari na 1: Matatar Petrochemical - Kula da Famfo Mai Juyawa (Centrifugal Pump Monitoring)

Wuri: Gulf Coast na Texas. Wurin ya haɗa modules 3500/42 guda goma sha biyu da Allen-Bradley ControlLogix L81 PLCs. Kowane famfo yana da ma'aunin kusanci biyu da aka dasa su a kusurwar digiri 90 a kan gidan bearing. An saita saurin ɗaukar samfur (sampling rate) zuwa 10 kHz tare da ƙudurin 16-bit. PLC ɗin yana yin binciken ainihin lokaci na kololuwa-zuwa-kololuwa (peak-to-peak) na girman girgiza sannan yana kwatanta ƙimomin da ƙa'idodin API 670 (faɗakarwa a 15 mm/s, haɗari a 25 mm/s).

A cikin watanni takwas, tsarin ya gano kurakurai goma sha ɗaya da ke tasowa: fashewar kejin bearing guda biyar, rashin daidaiton impeller guda huɗu, da yanayi biyu na rashin daidaito. Matsakaicin lokacin da aka gano matsalar kafin ta kai ga gazawa ya kasance kwanaki 14. Gazawar famfo ba tare da shiri ba ta ragu daga takwas a shekara zuwa biyu a shekara. Tanadin shekara ya kai $720,000. Kudin aikin kiyayewa da ya shafi girgiza ya ragu da kashi 40 cikin ɗari domin an rika tsara gyare-gyare maimakon yin su ne kawai lokacin da matsala ta faru.

Nazarin Lamari na 2: Samar da Wuta - Girgizar Shaft na Turbin Tururi

Wuri: North Rhine-Westphalia, Jamus. Masana'antar ta sa ido kan turbin tururin MW 150 guda shida ta amfani da modules 3500/42 da aka haɗa da Siemens S7-1500 PLCs da tsarin Siemens PCS 7 DCS. Kowane turbin yana da nau'i-nau'i biyu na ma'aunin kusanci XY guda huɗu a kan gidajen bearing. PLC ɗin yana aiwatar da ka'idar zaɓe (voting logic): rufe aiki (shutdown) yana bukatar aƙalla biyu daga cikin ma'aunai huɗu su wuce 28 mm/s a lokaci guda domin guje wa gazawar na'ura guda ɗaya.

Tsarin ya gano daurin turbin na lamba 3 yana fara samun rashin daidaito, tare da girgiza ta tashi daga 11 mm/s zuwa 19 mm/s a cikin sa'o'i 72. An kunna ƙararrawa a 18 mm/s. Ƙungiyoyin kiyayewa sun yi gyaran daidaitawa yayin lokacin dakatarwa na awanni biyu da aka tsara. Ba tare da haɗa tsarin ba, rashin daidaiton zai ci gaba har ya zama cikakken shafewa (full rub), wanda zai jawo awanni 12 na tsayawar aiki ba tare da shiri ba da kuma asarar kuɗin shiga na $500,000. Masana'antar ta kuma bayyana raguwar kaso 30 cikin ɗari a yawan sauya bearing bayan shekaru biyu na aiki.

Nazarin Lamari na 3: Sarrafa Sinadarai - Kariya ga Babban Mai Busar Iska mai Haguwa da Sauri

Wuri: Ulsan, Koriya ta Kudu. Masana'antar sinadarai tana aiki da masu busar iska 24 a saurin har zuwa 12,000 RPM. Injiniyoyi sun saita ƙa'idoji masu tsauri: faɗakarwa a 8 mm/s, rufe aiki (shutdown) a 12 mm/s saboda ɗanɗanar tsaurin tsarin aikin. Modules 3500/42 guda takwas suna aika bayanai zuwa Rockwell Automation CompactLogix PLCs ta hanyar Ethernet/IP. PLC ɗin yana aiwatar da lissafin saurin canji, yana kwatanta girgiza na yanzu da ƙimomin mintuna 10 da suka gabata.

Wannan lissafin saurin canji ya kama matsalolin rashin daidaituwa guda uku da ke tasowa a hankali cikin watanni shida. A kowane lokaci, an ga girgiza tana ƙaruwa da 0.8 mm/s a kowane awa. PLC ta yi gargaɗi ga ma'aikata awa huɗu zuwa shida kafin a kai matakin kashewa. An yi gyare-gyare a lokacin sauyin shifti ba tare da katse samarwa ba. Amfani da kayan ajiya (spare parts) ya ragu da kashi 50, kuma an kiyasta ajiya ta kai dala $350,000 a duk shekara.

Nazarin Lamari na 4: Dandamalin teku – Gaggawar kashe kwamfresan gas

Wuri: Tekun Arewa. Dandamali da ke da kwamfresoshi na gas guda huɗu na centrifugal. Muhalli mai tsanani ya buƙaci kariya mai takardar shaida SIL 2. An haɗa kayayyakin 3500/42 da PLC na Siemens mai kariyar kuskure (F-CPU). Lissafin tsaro ya yi amfani da na'urorin auna girgiza masu maimaita juna a kan kowane kwamfresa. Ana tayar da kashewa a 22 mm/s tare da dabarar zaɓen biyu-daga-cikin-biyu (two-out-of-two voting). Tsarin ya kuma ƙididdige canjin kallon yanayin girgiza (vibration trend derivatives) don hango gazawa a cikin taga na sa'o'i biyu.

A cikin tsawon shekaru uku, tsarin ya tayar da kashewa ta atomatik har sau huɗu saboda ƙaruwa a girgiza. Kowane abu ya hana mummunan haɗuwar impeller da kwanduna (casings). An kiyasta kuɗaɗen gyare-gyaren da aka kauce wa su sun kai dala miliyan $2.4. Bugu da ƙari, dandamalin ya cim ma rasa aiki sifili da suka shafi kwamfresan gas na tsawon watanni 36 a jere, idan aka kwatanta da gazawa biyu a cikin shekarun uku na baya.

Hanyoyi na ci gaba: Aunawar mataki da nazarin orbit

Baya ga sa ido kan girman girgiza (amplitude), 3500/42 na iya fitar da sigogin nuni na mataki (phase reference signals) idan aka haɗa shi da na'urar keyphasor probe. Wannan yana ba da damar ga PLC ta ƙididdige kusurwar matakin girgiza dangane da juyawar shaft. Ka aiwatar da lissafi (logic) da ke kwatanta matakin yanzu da ƙimomin asali da aka kafa lokacin kaddamar da injin. Sauyin mataki da ya haura digiri 30 sau da yawa na nuna lankwasawar shaft, rashin daidaiton zafi, ko makalewar coupling. Duk da cewa cikakken nazarin orbit yawanci yana buƙatar ƙwararrun software, sa ido na asali kan karkacewar mataki na aiki sosai a kan manyan PLC masu ikon lissafin lambobi masu digo (floating-point).

Jagorar aikace-aikacen magance matsaloli ga matsalolin haɗawa

Alamar matsala: Karatun da ke ta sauyawa alhali ba a sami canjin girgiza ba

Duba ci-gaban haɗin ƙasa. Auna juriya tsakanin tashar ƙasa ta 3500/42 da 'ground bus' na PLC. Kima da ta haura ohm 1 na nuna haɗin da bai yi kyau ba. Haka kuma a binciki yadda aka gama garkuwar igiyoyi (shields). Garkuwa da aka ɗaura wa ƙasa a ƙarshen igiya biyu na haifar da 'ground loops'. Tabbatar cewa ƙarshen garkuwa ɗaya kawai ke haɗuwa da ƙasa.

Alamar matsala: Kuskuren karkacewa na dindindin tsakanin 3500/42 da ma'aunin hannu

Sake daidaita (recalibrate) dukkan na’urorin biyu ta amfani da tushen ma’auni guda ɗaya. Tabbatar da daidaiton scaling a cikin saitin shigar analog na PLC. Kuskure da ake yawan yi shi ne saita nau’in kewayo daban: 3500/42 an daidaita shi zuwa 0-50 mm/s amma PLC an yi masa scaling zuwa 0-25 mm/s. Duba kuma ko akwai sassautaccen ɗaure na firikwensin. Accelerometers da aka matse da hannu kawai suna haifar da karatun da aka rage ƙarfi.

Alama: PLC ba ya Haifar da Shutdown Duk da Girgiza ta Wuce Kima da Aka Kafa

Duba tsarin jerin aikin shirin PLC (program scan order). Kimomin shigar analog suna sabuntawa ne ba tare da bin lokaci ɗaya da aiwatar da lissafi ba (asynchronously). Idan lambar da ke sarrafa shutdown ta yi kwatancen kimomi kafin a sabunta teburin shigarwa, jinkiri zai faru. Matsar da lissafin kwatancen girgiza zuwa periodic task mai mafi yawan lokacin zagaye 50 ms. Hakanan tabbatar cewa fitarwar ƙararrawa (alarm relay outputs) daga 3500/42 an haɗa su da madaidaitan terminals na shigar PLC kuma an daidaita waɗannan shigarwar don madaidaicin yanayin ƙarfin wuta.

Tambayoyin da Injiniyoyin Filin (Field Engineers) ke Yawan Yi

Ta yaya za mu daidaita ɗaukar samfurin girgiza a kan modules 3500/42 da yawa don nazarin jerin injuna (machine train analysis)?

Yi amfani da external trigger input na 3500/42. Haɗa siginar bugun jini guda (common pulse signal) daga digital output na PLC zuwa duk modules. Shirya PLC ɗin ya samar da trigger kowane daƙiƙa ɗaya. Daga nan kowane module zai ɗauki samfur (sample) a lokaci guda, wanda zai ba da damar auna bambancin yanayi (phase) tsakanin tashoshi daidai. Ajiye bayanan da aka daidaita a cikin jerin (arrays) na PLC don nazarin bayan abin da ya faru ko don loda su zuwa historians.

Menene iyakar tsawon kebul tsakanin 3500/42 da katin shigar analog na PLC ba tare da tabarbarewar sigina ba?

Don loops na ƙarfin lantarki 4-20 mA, tsawon kebul zai iya kaiwa mita 300 idan an yi amfani da kebul ɗin 18 AWG twisted-pair mai kariya (shielded). Siginar ƙarfin wuta (0-10 V) suna fi zama masu saurin samun cikas; takaita irin waɗannan layukan zuwa mita 50. Don dynamic buffered outputs, a ƙuntata tsawon kebul zuwa ƙasa da mita 15 domin a kiyaye martanin mita sama da 1 kHz. Yi amfani da line drivers ko signal converters don tafiye-tafiye masu nisa.

Za mu iya aiwatar da algorithms na kulawa kafin lalacewa (predictive maintenance) kai tsaye a cikin PLC ba tare da amfani da wasu software na waje ba?

Eh, cikin wasu ƙa'idoji. PLC na zamani da ke da ƙwarewar lissafi mai ci gaba na iya ƙididdige gangaren canjin ƙima (trending slopes), matsakaita masu motsi (rolling averages), da ƙimar saurin canji (rate-of-change). Wasu na’urorin sarrafawa na matakin sama suna goyon bayan ɗakunan karatu na FFT don ainihin nazarin spectral. Duk da haka, cikakken gano envelope da ƙididdige mitar lahani na bearing har yanzu suna buƙatar na’urorin nazarin girgiza na musamman ko edge gateways. Yi amfani da PLC don kariya a ainihin lokaci da saka idon yanayin canji na asali; fitar da bayanan asali zuwa wasu tsarin waje don zurfin bincike.