Dakata da Keɓantattun Alamomin PLC: Haɗin Edge da Ke Aiki

Haɗa PLC na Alamu Daban-Daban: Hanyoyin Fasaha da Mafi Kyawun Dabarun Injiniyoyi

Gaskiyar Masana’antu Kan Muhalli da ke Cike da PLC Daban-Daban

Masana’antu da yawa suna aiki da alamomin PLC daban-daban a sassa daban-daban na layukan samarwa. Kayan Siemens, Rockwell Automation, Omron, Mitsubishi, da Schneider Electric sau da yawa suna aiki tare a cikin wannan masana’antar guda. Wannan bambancin ya samo asali ne daga sabunta tsofaffin tsarin, haɗewar kamfanoni, da dabarun siyan mafi kyawun kayan aiki daga kowane ɓangare. Bisa la’akari da binciken da aka yi a fiye da masana’antu 50, ƙasa da kashi 12% ne kawai ke amfani da alamar PLC guda ɗaya. Sauran kashi 88% suna sarrafa tsakanin alamomi biyu zuwa biyar na masu sarrafawa a kullum.

Gandun-Tsuntsaye a Matakin Yarjejeniyar Sadarwa Tsakanin Alamu na Masu Sarrafawa

Kowane alamar PLC na aiwatar da nasa keɓantaccen yarjejeniyar sadarwa. Siemens na amfani da sadarwar S7 a kan ISO-on-TCP don jerin S7-1200 da S7-1500. Rockwell Automation na amfani da EtherNet/IP tare da saƙonnin CIP (Common Industrial Protocol). Omron na amfani da yarjejeniyar FINS ko kundin sadarwar jerin NY. Mitsubishi na dogaro da yarjejeniyar MC a kan TCP/IP. Ba za a iya aika bayanai kai tsaye daga mashigin sarrafawa na alama guda zuwa wani alama dabam ba sai an samu matakin fassarar tsakanin su. Wannan takura na tilasta ma’aikata su rika ɗaukar bayanan samarwa da hannu daga allon HMI dabam-dabam ko kuma su sake ginawa dashboard daga manyan tushe na bayanai da yawa. Yin wannan aikin da hannu na cin kusan awanni uku a kowane mako ga kowace layin samarwa kuma yana jawo kuskuren rubutu wanda zai iya katse tsarin ƙera kaya.

Takurawar Hanyoyin Haɗa Kaya na Gargajiya

Sabar OPC Classic da OPC UA su ne hanyar da aka fi amfani da ita wajen haɗa PLC na manyan masu ƙera daban-daban. Waɗannan sabobin suna kawo wasu takurawar aiki. Suna zama wuri guda na gazawa a cikin cibiyar sarrafawa. Suna buƙatar ci gaba da sarrafa lasisi da kuma akai-akai sabunta tsarin aiki na Windows. Suna wahalar riƙe ingantaccen aiki idan ana maganar bayanan sarrafa motsi mai sauri sosai da ke buƙatar lokacin duba (scan time) ƙasa da milisekan 5. A wani shigarwa da aka rubuta a wani masana'antar kera motoci, wata gada ta OPC ta gamu da abubuwan gazawa 12 a cikin zangon aiki guda saboda sabuntawar Windows ta atomatik. Masu juyar da yaruka (protocol converters) kamar ƙofar Profinet-zuwa-EtherNet/IP suna ƙara jinkiri na milisekan 10 zuwa 30 kuma ba za su iya sarrafa damar shiga sigogi na acyclic ko kuma ƙarin bayanan binciken na'ura ba.

Mimarin Haɗaɗɗen Haɗin Kai Bisa Orchestration

Gine-ginen da ya fi tasiri yana ɗaukar kowace alamar PLC a matsayin na'ura ta musamman a cikin babbar tsarin aiki ta atomatik. Siemens controllers suna da ƙwarewa a sarrafa tsari mai rikitarwa tare da ci-gaba a daidaita PID da blocks na sarrafa zafin jiki. Rockwell controllers suna bayar da ingantaccen sarrafa motsi mai sauri ta hanyar integrated axis architecture da Kinetix drive systems. Omron controllers suna bayar da event-driven task scheduling wanda ya dace da jerin ayyukan marufin kaya. Maimakon maye gurbin ko sake shirya controllers da ake da su, injiniyoyi ya kamata su bar native code ɗinsu yadda yake su ƙara matakin middleware na sadarwa a kai. Wannan hanyar tana kauce wa tsada da haɗarin sake rubuta Siemens SCL function blocks zuwa Rockwell Structured Text ko akasin haka.

Edge Computing don Daidaita Bayanai daga PLCs na Nau'o'in Alamu da Dama

Hanyar haɗin gargajiya mai dogaro da polling tana aika maimaitattun buƙatun bayanai daga uwar garke ta tsakiya kowane milisekondi 100 zuwa 1000. Wannan hanyar tana ƙara cunkoson cibiyar sadarwa kuma tana jinkirta amsoshin ainihin-lokaci. Edge computing tana sanya ƙananan nodes na sarrafawa kusa da kowane PLC ko rukuni na PLCs. Waɗannan nodes ɗin suna amfani da native driver libraries na kowace alama. Ga Siemens controllers, node ɗin yana amfani da libnodave ko Snap7 libraries don karanta S7-1200 da S7-1500 data blocks. Ga Rockwell, yana amfani da CIP ta Ethernet tare da explicit messaging don karanta tag arrays. Ga Mitsubishi, yana amfani da MC protocol ta TCP/IP. Daga nan edge node ɗin yana daidaita bayanan da aka tattara zuwa tsari guda, yana aiwatar da ƙa'idodin tacewa, sannan yana kunsa ragowar bayanan da MQTT ko Sparkplug B protocols don tura su zuwa tsarin tsakiya.

Wata masana'antar sarrafa roba da ta aiwatar da wannan gine-ginen edge ta samu raguwar nauyin sarrafa bayanai a uwar garke ta tsakiya da kashi 73%. Jinkirin isar bayanai (latency) ya ragu daga milisekondi 800 zuwa ƙasa da milisekondi 50. Edge node ɗin ya ajiye ƙimomin da ba sa canzawa, kamar sunayen na'urori da scaling factors, a cikin gida, yana tura ne kawai canje-canjen sigogin aikin da suke motsi. Tacewar deadband ta hana aikawa da canje-canjen ƙima da ba su da muhimmanci. Karatun zafin jiki da ke rawa tsakanin 100.0 da 100.1 digiri bai tayar da kowace aika sakon cibiyar sadarwa ba. Sai bayan ƙimar ta ketare matakin 101.0 digiri ne node ɗin ya aika sabuntawa. Wannan ya rage zirga-zirgar cibiyar sadarwa sau 40 ga matakan samarwa da ke daidaitacce.

Tsarin Tace Bayanai don Aikace-aikacen Masana'antu

Tattara dukkan bayanan da suka fito daga kowane PLC na haifar da yawan buƙatar ajiya da nazari. Yawancin bayanan da ake tarawa ba sa taɓa taimakawa wajen yanke shawarar aiki ko ƙirƙirar faɗakarwa. Tsarin matakan tacewa mai inganci yana ƙara ingancin tsarin.

• Matakin farko na tacewa: A yi watsi da duk ƙimomin da suka rage suna cikin madaidaitan iyakokin aiki na al'ada.
• Mataki na biyu na tacewa: A ajiye alamar lokaci (timestamp) kawai idan ƙimomi sun ketare iyakokin da aka ayyana.
• Mataki na uku na tacewa: Ga mahimman sigogi masu alaƙa da tsaro, a ajiye cikakken bayanin asali (raw data) na tsawon kwanaki 30. Ga sigogin da ba su da mahimmancin tsaro, a ajiye ƙimomin da aka taƙaita na kowace rana kawai.

Ajiyar Bayanai na Asynchronous don Haɗa Hanyoyin Sadarwa (Protocol Bridging)

Haɗa hanyoyin sadarwar PLC daban-daban yana buƙatar fahimtar bambance-bambancen halayen lokaci (timing behavior). Profinet IRT na iya kaiwa lokacin zagaye (cycle time) ƙasa har zuwa microseconds 31.25 amma yana buƙatar kayan aikin cibiyar sadarwa da aka daidaita lokaci. EtherNet/IP implicit messaging kuma yawanci yana aiki ne da ƙimar RPI (Requested Packet Interval) tsakanin milliseconds 2 da 100. Haɗa na’urar Profinet mai sauri kai tsaye zuwa cibiyar EtherNet/IP mai jinkiri yana haifar da matsin baya (backpressure) wanda ke rage ingancin aiki. Amfani da ajiyar bayanai na asynchronous (asynchronous buffering) ne ke magance wannan matsalar. Na’urar gada (bridge device) tana karanta bayanai daga cibiyar sadarwa mai sauri zuwa kundin ajiya mai tashoshi biyu (dual-port memory buffer). Cibiyar sadarwa mai jinkiri kuma tana karanta daga wannan kundin a lokacin ta. Wannan yana raba (decouple) lokutan zagaye biyu. Dole ne kundin ajiya ya sami zurfin da ya isa don sarrafa mafi girman bambance-bambancen cunkoso (peak burst). Ga na'urar Profinet da ke aika ƙimomi 1000 a kowane millisecond zuwa na’urar EtherNet/IP da ke karantawa kowane milliseconds 10, kundin ajiyar dole ne ya iya rike aƙalla ƙimomi 10,000. Idan kundin ya yi ƙanƙanta, zai cika (overflow) a lokacin kololuwar samarwa kuma ya haifar da gazawar haɗin kai.

Canjin nau'in bayanai dole ne ya guji yankewa ko kurakuran zagaye (rounding errors). Ana ba da shawarar gwajin bin ƙa'idar IEEE 754 kafin a sanya kowace ƙofa haɗa bayanai (integration gateway) cikin aiki. Kuskuren daidaita biti ɗaya kawai a cikin umarnin saurin mota na iya haifar da lalacewar inji.

Gudanar da Rayuwar PLC Bisa Haɗari (Risk-Based PLC Lifecycle Management)

Na'urar sarrafa kwandon isarwa (conveyor belt PLC) da na'urar sarrafa tukunyar reactor (reactor vessel PLC) suna aiki ne a karkashin yanayi daban-daban ƙwarai. Kwandon isarwa yana yawan fuskantar fara-tsayawa akai-akai amma da ƙaramin girgiza. Tukunyar reactor kuma tana aiki ba tare da yankewa ba a ƙarƙashin zafi mai yawa da kuma fuskantar sinadarai. Idan aka yi amfani da jadawalin kulawa iri ɗaya ga duka na'urorin sarrafan, hakan yana janyo lalacewar wuri-wuri ga na’urar da ake matsa wa lamba sosai ko kuma musanya mara amfani ga na’urar da ake amfani da ita kaɗan. Ya kamata a raba na’urorin sarrafan zuwa rukunan haɗarin (risk profiles) bisa yanayin aiki.

• Bayanan haɗarin zafi (yanayin zafi na waje sama da 50°C): Sauya “electrolytic capacitors” duk bayan awanni 40,000 na aiki. Tsufar capacitor yana bi samfurin Arrhenius. Kowace ƙarin 10°C na zafin jiki yana rage rayuwar aikin capacitor da 50%.
• Bayanan haɗarin inji (girgiza sama da 0.5g): Duba mahaɗan “backplane” da “terminal blocks” kowane watanni shida. Girgiza na sassauta dunƙulen “screw terminals”, yana haifar da katsewar haɗi lokaci-lokaci waɗanda ke da wahalar gano su.
• Bayanan haɗarin lantarki (muhallin wutar lantarki mara kwanciyar hankali): Sanya tsarin UPS na kan layi kuma ku sa ido kan “DC bus ripple”. Ripple da ya wuce 10% yana nuna yiwuwar gazawar tacewar wutar lantarki da ke gabatowa.

Tsarin Yanke Shawarar Siyan PLC

Yanke shawarar saye bisa farashin na’ura kaɗai sau da yawa yana watsi da jimillar farashin mallaka. Mai kula mai rahusa na iya rasa goyon bayan yarukan sadarwa na asali da ake amfani da su a cikin shuka, kuma kuɗin haɗawa na iya cinye duk wata riba ta farko. Ana kan-wa-kan-ce sayen PLC masu matakin tsaro don aikace-aikacen da ba na tsaro ba saboda rangwamen mai siyarwa. Wannan dabara tana ɓata kasafi kuma tana karkatar da kayan tsaro da aka tabbatar daga aikace-aikacen da gaske suke buƙatarsu. Matattarar yanke shawara bisa matakin Safety Integrity Level (SIL) tana inganta sakamakon saye.

• Buƙatar SIL 2 ko fiye: Zaɓi PLC mai matakin tsaro tare da “function blocks” da aka tabbatar.
• Babu buƙatar tsaro: Zaɓi PLC na al’ada tare da daidaitacciyar ƙirar I/O mai rage kuɗi.

PLC masu matakin aminci (safety-rated) na gudanar da gwaje-gwajen gano matsala a kowane zagayen “scan”, wanda ke ƙara lokacin “scan”. Amfani da PLC mai tsaro a aikace-aikacen marufin da ke aiki da sauri yana rage yawan aiki. A wani shigarwa da aka rubuta, an girka Siemens ET 200SP Failsafe controller a kan wani sashen “conveyor” mai sauƙi. Lokacin “scan” na millisecond 150 na CPU ɗin tsaro ya haifar da yankin tara kaya (accumulation zone) na sakan 1.5. Sauya shi da ET 200SP na al’ada ya rage lokacin “scan” zuwa millisecond 8 kuma ya kawar da tangardar.

Gyaran Hasashe Mai Aiki Ta Amfani da Bayanin PLC da Ake da Shi

Dashboard ɗin gyaran hasashe da ke amfani da alamun gani da yawa sau da yawa suna ba da bayanai fiye da yadda ma’aikata za su iya sa ido a kansu yadda ya kamata. Faɗakarwar sauƙaƙan ƙa’ida (threshold) ga muhimman sigogi sukan gano yawancin nau’ikan gazawa. Gazawar bearing tana haifar da ƙaruwa a girgiza da zafin jiki da za a iya gano su sa’o’i kafin gazawa ta cika. Ƙarin zafin jiki na 40°C baya buƙatar kowace hanyar koyo na injin (machine learning) domin a gane shi. Ya kamata a fifita saka kuɗin “automation” a kan sa ido na asalin ƙa’idojin ƙofa (basic threshold monitoring) da farko. A ƙara koyo na injin ne kawai idan akwai tsare-tsaren gazawa masu rikitarwa da ma’aikata ba sa iya gane su da sauƙi. Manyan majiyoyin bayanai uku ne ke tallafawa gyaran hasashe bisa PLC.

1. Rajistar ganowa (diagnostic registers) a cikin PLC ɗin da kansa. Siemens tana samar da faɗaɗɗen bufers na ganowa da ake iya samu ta SFB 52 (RDREC). Rockwell tana samar da umarnin GSV (Get System Value) don dawo da matsayin module.
2. Bayanan tashoshin I/O ciki har da yanayin sauye-sauyen shigar analog (analog input trends).
3. Kididdigar sadarwa kamar adadin sake gwadawa (retry counts) da kuskuren CRC (Cyclic Redundancy Check). Ƙaruwa a ƙimar kuskuren CRC a kan sashen Profibus na nuna lalacewar matakin jiki kafin cikakkiyar gazawa.

Ana iya aiwatar da tsarin hasashen (predictive) mai araha wanda ke amfani da bayanan PLC da ake da su kawai a matsayin routine na bango a cikin babban controller. Routine ɗin yana bin diddigin farawa-da-tsayawar mota, yana kwatanta ainihin lokutan zagaye da ƙimomin da ake tsammani, kuma yana haifar da gargadin kiyayewa idan lokacin zagaye ya ƙaru da kashi 15% sama da matakin farko. Wannan hanyar ta gano bawul mai makalewa a cikin hydraulic press makonni biyu kafin bawul ɗin ya gaza gaba ɗaya, wanda ya ba da damar maye gurbinsa a lokacin tsarin tsaida aiki da aka tsara maimakon tsaida samarwa na sa’o’i takwas ba da gangan ba.

Misalin Fasaha: Gada tsakanin Siemens S7-1500 da Rockwell CompactLogix

Wani mixing skid da Siemens S7-1500 ke sarrafawa yana ciyar da samfur zuwa layin marufi da Rockwell CompactLogix ke sarrafawa. Mixing skid ɗin dole ne ya aika matsayin kammala batch, zafin jikin ƙarshe na samfur, da ƙimar danko zuwa layin marufi. Layin marufi kuma dole ne ya dawo da siginar shiryawa (ready signal) da adadin kayan da aka ƙi zuwa mixing skid ɗin. OPC UA connection yana ƙara kwamfutar Windows a matsayin yiwuwar wurin gazawa. Edge gateway mai ɗauke da native S7 da CIP drivers yana bayar da mafita mai ƙarfi fiye da haka.

Gateway ɗin yana karanta DB100.DBD0 (matsayin batch a matsayin DINT) da DB100.DBD4 (zafin jiki a matsayin REAL) daga Siemens controller kowane milisakan 100. Yana rubuta waɗannan ƙimomin zuwa Rockwell tags da ake kira Mixer_Batch_Status da Mixer_Temperature. Don alkiblar baya, gateway ɗin yana karanta Rockwell tags Pack_Ready (BOOL) da Pack_Reject_Count (DINT) kowane milisakan 500 kuma yana rubuta su zuwa Siemens DB200.DBX0.0 da DB200.DBD2. Gateway ɗin yana sarrafa juyin nau’in bayanai ta atomatik. An aiwatar da sa ido na heartbeat kamar haka: idan gateway ɗin ya rasa zagayen karatu uku a jere daga kowanne PLC, yana saita gargaɗin tsarin kuma yana tilasta fitarwa su koma yanayin kariya.

Wannan daidaitawar tana aiki da tabbas a kan na’urar Raspberry Pi ta masana’antu mai real-time kernel, tare da farashin kayan aiki kimanin dala $400. Jimillar farashin haɗawa da shirin kwamfuta ya kai dala $3,200. Cikakken maye gurbin PLC don daidaita dukkan nau’ukan zai kashe dala $85,000 tare da karin makonni uku na tsaida samarwa.

Nazarin Lamari: Haɗa Nau’o’in PLC Daban-daban a Wata Masana’antar Samar da Siminti

Wani mai samar da siminti a Kudu maso Gabashin Asiya yana da nau’o’in PLC guda biyar daban-daban a sassan nika dutse, tanda (kiln), da shiryawa. Ma’aikatan fasaha suna shafe kwana biyu cikakku a kowane wata suna daidaita rahotannin samarwa daga tsarin daban-daban. An girka na’urorin gefen cibiyar da ke amfani da Node-RED a kan kwamfutocin masana’antu a matsayin mafita ta haɗin kai. Kowace na’ura tana gudanar da akwatunan Docker daban-daban don layin sadarwar kowane irin PLC. Akwatin Siemens ya yi amfani da kunshin node-red-contrib-s7. Akwatin Rockwell ya yi amfani da kunshin node-red-contrib-cip-ethernet-ip. Akwatin Modbus ne yake sarrafa na’urorin Schneider Electric da na’urorin kamfanoni na uku.

Na’urorin gefen cibiyar sun tara bayanai a cikin gida sannan suka buga nau’in bayanai na JSON da aka daidaita zuwa ga uwar garken MQTT. Babban allon kulawa na Node-RED ya yi rajista da batutuwan (topics) na MQTT sannan ya nuna ƙididdiga guda ɗaya da ta haɗu daga dukkan nau’o’in iri. Jimillar kuɗin kayan aiki da software bai wuce dala $15,000 ba. Lokutan tsayawar aiki ba tare da shiri ba sun ragu da kashi 27% cikin watanni huɗu bayan ƙaddamarwa. Masu lantarki ba sa buƙatar ɗaukar kwamfutoci uku daban-daban na shirin PLC. Yanzu suna haɗawa da kowanne PLC ta hanyar gidan yanar gizon tashar umarnin na’urar gefen cibiyar.

Taswirar Aiwanawa ga Masana’antu Masu Amfani da Nau’o’in PLC Daban-daban

Fara da rubuta bayanin kowane PLC a ɗakin masana’anta tare da iri, samfur (model), sigar firmware, da ka’idojin sadarwa da yake tallafawa. Ƙirƙiri takardar lissafi (spreadsheet) mai ginshiƙai na adireshin IP, nau’in yarjejeniya (S7, EtherNet/IP, Modbus TCP, FINS, MC protocol), lokacin sikan (scan time) da ake buƙata, da matakin muhimmanci. Gano manyan kwararan bayanai guda uku mafi daraja waɗanda yanzu haka ke ketare iyakar samfura daban-daban. Zaɓi ɗaya daga cikin ƙananan ƙwayoyin samarwa da ba su da matuƙar muhimmanci a matsayin yankin gwajin haɗin kai. Sanya buɗaɗɗen gadar yarjejeniya (protocol gateway) ko na’urar gefen cibiyar (edge node) ne kawai don wannan ƙwayar. Auna adadin lokacin da ma’aikata suka tsira da raguwar kuskure. Kaɗai ka faɗaɗa zuwa ƙarin ƙwayoyin samarwa bayan ka tabbatar da ingantattun canje-canje masu aunuwa.

Domin gwaji ba tare da babban kuɗin kayan aiki ba, ka zazzage ɗakin karatu na Snap7 don gwajin sadarwa na Siemens. Snap7 yana aiki a kan Windows, Linux, da macOS. Don gwajin Rockwell, yi amfani da libplctag, wanda ke tallafawa tsoffin PLC5 da sabbin na'urorin sarrafa CompactLogix. Duk ɗakunan karatun nan buɗaɗɗen tushe ne kuma suna da al’ummar masu amfani masu aiki. Gina ƙaramin rubutaccen shiri na Python wanda ke karanta alama (tag) ɗaya daga kowace alama ta kowanne iri, sannan ya buga ƙimomin a kan kwamfutar umarni (console). Wannan yana tabbatar da asalin haɗin kai kafin a saka jari cikin na’urorin kayan aiki.

Game da Marubucin

An rubuta shi ne ta Gu Jinghong, injiniyan sarrafa masana'antu na PLC & DCS, mai ƙwarewa a mafita ga kamfanonin mai, iskar gas da sinadarai.